"iSquint is an iPod video conversion app. It's up to 5 times faster than Apple's method, works well with AVIs and MPEGs, and it's infinitely free-er.
It's also rather easy.
Drag in your file, click 'Start', and away you go. You can even set screen-size and quality preferences.
On a 1.5GHz G4, iSquint can convert most video files to iPod-screen-sized videos in realtime. Depending on a few factors, a 20 minute video will take up anywhere from 50-150MB of disk space."