iPod help?

Right, so I have this iPod, and it's cool because it has a wider screen that's just perfect for videos and everything, only. I want some pretty short videos, not MTVs, maybe cartoon episodes or something, but I don't really know WHERE I could possibly get videos. I'd do iTunes but they don't allow non-US accounts or soemthing. The videos need to be MPEG 4, right? Is there a WAY to convert AVI or WAV files to MPEG 4? Help, anyone? :\