Using Quicktime Pro
From The Neuros Technology Wiki
Using Quicktime Pro 7.03+ to put video on your iPod
This is naturally the easiest software to use for converting video to iPod-compatible formats. Assuming you have installed and upgraded to Quicktime Pro 7.03, there are only a few steps to follow:
Step 1: Open the program. Now, load your (quicktime-playable) movie in QT.
Step 2: Go to File - Export, and choose a location for your converted movie.
Step 3: Select the iPod output format, "Movie to iPod". Hit "Save".
Step 4: Wait for it to encode, and when it's done, drag the file to iTunes, from where you can move it to your iPod.
Pros: *No guesswork *Designed to be simple
Cons: *Costs $30.00 *Very little control over output quality *Slow *Input formats limited