Try Betaplayer, together with my app, PocketDVD
(www.pocketdvd.ca
)
there is even a review on this site that gives you more details about the optimisations for DSTN screens.
http://www.hpcfactor.com/qlink/?linkID=92
I love watching movies on my NEC MP900, even more then on the more then capable ipaq 2210 I used to use before it.
It's all a matter of the framerate.