While I have never personally modified my iPod, I have done research into it. The majority of iPod mods come from the iPod Linux Project, a very neat project devoted to taking full advantage of the power of the iPod. Running Linux on your iPod can allow you to play videos on non-video iPods, add more games to your iPod, and much, much more.

To do the majority of my research, I have always turned to iLounge. While iLounge is more of an iPod support forum, they do have some great resources and communities setup for letting you do more with your iPod. If you ever have a question about your iPod, or just want to see what else your iPod can do, I would check out iLounge before you go anywhere else.