After building up a good deal of buzz, Realmac Software has released Courier, a file sharing utility for Mac OS X that lets you quickly and conveniently share files on your Mac to multiple online services.
Adding to its appeal, Courier integrates your envelopes with the Mac OS X Services menu (available via right-click or the current application menu), making it easy to share items from anywhere in Mac OS X.
Realmac also offers a plug-in API, so we can expect a number of third party plug-ins—TwitPic and CloudApp plug-ins are already available.
A demo that allows five deliveries is available. Courier is priced at $20 as a limited introductory offer and requires Mac OS X 10.6 running on a 64-bit Mac. It currently supports Facebook, Flickr, YouTube, Ember, Amazon S3, Vimeo, and FTP/SFTP, with more services on the way.