SiK ram din
The dock connector port on 3G and later iPods and all iPod minis provides impressive functionality, including line-level audio out and FireWire connectivity. Unfortunately, to tap into those connections, you need either Apple's dock base or a third-party adapter. In the past we've recommended both SendStation's compact PocketDock adapters and SiK's din. The din plugs into the iPod's dock connector port and provides a FireWire port (for charging and data connectivity) and a line-level audio minijack at the end of two 7-inch cables.
SiK's new version of the din, called the ram din, differs from the standard din in that instead of a line-level minijack, which requires an additional cable to connect the minijack to your audio system, the ram din provides a standard L-shaped miniplug that can be plugged directly into a set of portable speakers, a portable headphone amp, or even the auxiliary input jack on a car stereo.
If you need a cable longer than 7" to connect your iPod to your audio system, or if you want something more compact, SendStation's $30 PocketDock Line Out is probably a better choice. But for use with a portable headphone amplifier or portable speakers (or anywhere a short cable is preferred) the ram din is a nice little accessory. It lets you get quality audio directly from your iPod into a portable audio setup, and it lets you use any FireWire cable to charge your iPod on the go -- no need to carry your iPod's dock connector cable if you've already got a FireWire cable handy.
SiK ram din
FireWire adapter with audio line-out jack for dockable iPods