Ideal Video encoding

Hi guys. I've had it up to here (puts hand way above head) with video encoding for the PSP. I've tried many programs: Any Video Converter, Xilisoft, PSP Video 9 etc, but I've always had a problem. Either:
a) It doesnt end up fullscreen
b) The sound is crap quality
c) The video is crap quality
d) The audio and video are not in sync

And a host of other problems. Now I know the basics of how to make video and sound quality good, but I cant seem to bring all these things together. Plus Im REALLY confused about which resolution is fullscreen:368x208 or 480x272

Can someone please tell me a foolproof way to encode videos that will work every time?

i have 3.71 m33

480x272 is the fullscreen resolution

I know but I've encoded before in 368x208 and that was fullscreen too! thats why im confused

If it's under 480x272 it's simply streched to fullscreen.

ok ok ok ok ok that's all well and good, but let's not forget the question at hand people! (see bold in first post)