Dude, forget all this confusing crap.
The Core Pocket Media Player (TCPMP) version 0.72RC1 and it has plugins for extended functionality (for playing more formats).
The new version (v1.0, called CorePlayer) lost support for mpeg2, but it has better support for mp4. I think version 1.0 will be improved and will add mpeg2 support soon.
The pocket PC can play mpg2 just fine! I pull video off my PVR (Tivo/ReplayTV and it plays fine.
Do a search on google for either, but here are a couple of links that should work.
http://picard.exceed.hu/tcpmp/test/
http://www.coreplayer.com/
http://tcpmp.corecodec.org/download/