I often get the question of, "I downloaded this video from YouTube, how do I play it on my iPod?" Or, "I created this video, but it's huge. How can I make it smaller?"
The program I use for both of these is Super. Super is a great tool for converting videos. It will convert just about any form of video into any other format. One of the cool bits is the list of presets. Just select the one for your device (like iPod, PSP, Sony Ericsson) and all of the settings will be just right.
Or, if you know more than me, you can tweak your video codec choice and internal encoders (I have no idea what this means).
Anyway, You can get it from the official download site, but I don't recommend this. You have to search and search for the link (it's on the third page you have to click through). Or you can Google it and download it from somewhere else.It works great in Windows XP, I haven't tried it in Vista yet.