For some people, downloading files is something that happens only occasionally—for example, when a new version of a program they use is available. But for others, file downloading is a frequent task. I’m definitely in the latter group; for my Mac Gems work alone, I download 10 to 20 software titles each day.

Safari, Firefox, and other Web browsers handle downloads adequately, but if you’re a frequent downloader, a dedicated download manager can be quite handy. The latest such tool is Many Tricks’ Leech 1.1.2 ( ; €9.95; cross-upgrade from any other download-managing utility, €6.95), and in the time I've been testing it, it's improved my workflow noticeably.

Leech provides several options for initiating a download. One is to drag or paste a download’s URL into the Leech window; the file will begin downloading immediately. (When you paste a URL or link, using the Command+V keyboard shortcut or Leech’s Edit: Paste menu command, you won’t actually see the URL in a text field; Leech will just start downloading from the pasted URL.) You can also drag a URL onto Leech’s icon in the Dock or switch to Leech and enter a URL manually using the File: Open URLs command. (All these methods also work with multiple URLs. For example, you can copy several URLs at once and then paste them into Leech’s window.) You don't even have to use raw URLs; you can even use text with embedded links. So, for example, you can drag or paste a paragraph of text from a Web site into Leech; Leech will extract all the download URLs from that paragraph.

But the easiest approach—though it comes with a caveat, noted below—is to let Leech integrate with your browser. When you first launch Leech, it will ask you if you want to install the necessary support files. If you agree, Leech can take over all download links in Safari, Camino, OmniWeb, and Firefox; it essentially displaces each browser’s own Downloads window. All you have to do is activate Leech from within your browser; for example, in Safari, you just choose Safari: Download via Leech. Once you do this, clicking on a download link in your browser sends the URL directly to Leech, where it then downloads.

The caveat I mentioned about this direct browser integration is that it requires you to install an Input Manager module; specifically, the SIMBL Input Manager manager. Input Managers like SIMBL use unsupported methods to add functionality to programs, so it’s possible they can cause problems, especially when new versions of affected programs, or the OS itself, are released. I use the occasional Input Manager hack on my own Macs without problems, but if you start experiencing issues with your Mac, especially after upgrading OS X or your Web browser, Input Managers are a good place to start troubleshooting. And I give Many Tricks much credit for being up front about Leech’s use of an Input Manager: before installing it, Leech provides you with detailed information about the risks. (Note that integration with Firefox requires that you also install the FlashGot extension and then choose Leech as your download manager in FlashGot’s preferences.)

However you choose to use Leech, you monitor your downloads using its main window, which looks very much like Safari’s Downloads window, complete with progress bars showing you how much of each file has been downloaded.

Of course, if all Leech did was to take over downloads from your browser, it wouldn’t be very compelling. What makes Leech so useful is that it gives you many options for customizing how downloads are handled.

At the most basic level, Leech lets you pause and resume downloads for individual files or for all downloads; paused downloads remain queued even if you quit Leech or shut down your Mac, so you can resume at some other time. (Note that some servers don’t support resumed downloads; downloads from such servers will start over when you resume.) Leech also lets you choose how many downloads can occur simultaneously; how and when downloads are cleared from the Leech window; and what kind of notifications you get when each download finishes (Leech includes Growl support). But it’s also got a number of unique features that make it especially useful for heavy downloaders:

• You can set up multiple download locations and then quickly switch between them. For example, during the normal course of my work day, most of the stuff I download ends up in work-related folders. But once a day I get an email from VersionTracker listing all the new programs added to VersionTracker that day; I go through this email and download new programs I want to try and updates to programs I’ve already installed. With Leech, I can easily choose to download such files to a folder dedicated to software downloads. (Such a change applies to future downloads; currently-downloading files will be saved to the location that had been chosen at the time they started downloading.) You can also choose to download a specific file to a different location by holding down the Shift key as you drag the download URL into Leech.

• You can configure rules for handling downloads of specific types or from specific domains—or both. For example, you can set up a rule so that any disk image downloaded from Apple’s servers is saved to a folder called “Apple Updates.” To do so, you choose File: Define Rule; enter apple.com and appldnld.apple.com.edgesuite.net in the Host box and dmg in the Extensions box; and then choose the desired folder—Apple Updates, in this example—from the Download To pop-up menu. (I included appldnld.apple.com.edgesuite.net in the Hosts box because some Apple updates actually come from that domain; note that you need to omit the . from any file extension.) If a rule contains a file-extension condition, you can optionally have Leech open matching files with a particular program. You can create as many rules as you need, and you can preview your rules in Leech’s File menu.

• Leech offers a number of of post-download options. Right-click on a completed download in Leech and you’re presented with a number of choices, including revealing or opening the file, copying the URL of the original download, or copying the path to the file on your Mac’s hard drive.

• If you’re not online, you can choose to download files later. For example, if you’re browsing email on a plane, or surfing pre-loaded or archived Web pages away from a network, Leech can queue downloads; you can then start the queue the next time you’ve got a ‘net connection.

• Leech’s downloads window also serves as a history listing, storing as many past downloads as you choose—up to the 500 most-recent, or, instead of a set number, the complete list of every file you’ve downloaded using Leech. What makes this feature useful is that you can sort the download history chronologically or by name or progress, and you can quickly search for any past download using the Filter field at the top of the window. Leech’s History menu also displays completed downloads and offers many of the same options you get by right-clicking on an item in the queue; the menu also adds an option to download a file again.

• You can set Leech to automatically shut down your Mac when all downloads have completed. If you’re downloading a huge file late at night, just right-click anywhere in Leech’s file list and choose Shut Down When Done; you can go to sleep knowing that your Mac will turn off by itself. (Of course, as with any shut-down command, make sure you don’t have any unsaved changes in other programs, which can prevent a shutdown from occurring.) Unfortunately, there's no Sleep When Done option.

• Leech’s Dock icon lets you track your downloads at a glance by showing the number of items in the queue and the overall progress of pending downloads.

There are also a few other interesting features, such as private downloading, which obfuscates file names in the download window, and keychain support, so you can re-download a file from a password-protected server without having to enter the password again.

One issue I found while testing Leech is that it doesn’t appear to support HTTP-redirect URLs. For example, all download URLs on VersionTracker are HTTP links such as http://tc.versiontracker.com/product/redir/lid/1369259/ScriptLight%20Install.dmg.zipScriptLight that redirect to the actual download URLs on software vendors’ servers (in this example, http://www.hamsoftengineering.com/assets/ScriptLight%20Install.dmg.zip). When Leech is integrated with your Web browser, such URLs present no problems, as your browser handles the redirect and passes the actual download URL to Leech. But if you try to paste such a URL into Leech, or drag it into Leech, nothing will happen, because Leech doesn’t see it as a valid download URL. That said, if you take advantage of Leech’s browser integration, which I suspect most people will, this issue won’t affect you.

Leech isn’t for everyone; if you don’t download files frequently, you won’t be able to appreciate its attributes. But for heavy downloaders, it’s the “Downloads window” I wish Safari and other browsers had.

Leech 1.1.2 requires Mac OS X 10.5 or later.