handbrake is an application designed for taking your DVDs and converting them to a format compatible with iPods, iPhones, AppleTV or PSPs (along with others). It has been reworked with version 0.9 to update some of the interface, is available for windows too (which i need to try).
i have been working on getting some DVDs to my laptop (no iPod video right now) for my commute. i have been using MacTheRipper along with toast/popcorn to get the file into a smaller format for storage on the mac and playback easily (without actually having a DVD spinning in the drive).
if you have any mobile technology and want to be able to view a movie while in transit (or move a DVD collection to a format you can playback on AppleTV), check out the above tools. it may be well worth the time or $100 you may spend to have a video collection at your finger tips.