There’s a project that has been underway for awhile called PocketDivXEncoder. It’s purpose is to provide a quick and easy way to convert video files to a shrunk down version that will fit the parameters of your handheld.
The two output formats are .ogm and .avi which makes it easy to play the files on your handheld using programs like TCPMP. It allows you to crop the video, scale down the video and audio, and see the total output file size. The output quality is excellent and you’ll be surprised how great the quality can still be when you shrink the movie to 180MB or less! The best part is its free! However, please support the author of the program.
More recently, the program was turned over into a different project called Lathe which has more features and a nicer GUI. You can watch a demo video of Lathe here.