You might also want to try
PocketTV its the standard for pocket pc video (this is for mpeg files).
You can edit the size and other aspects of a video (mpeg & others) with several different programs, the one I use is
TMpgEnc
I dont exactly know what you mean by mp3 compressor, an mp3 is already quite compressed, you can re-record it with a lowet bitrate and stuff or jsut rip a cd usign windows media player to get wma files that are smaller then mp3s and still sound good. You can use Winamp if you want to try to make your mp3s smaller as well, go to options and look around in there.