The program you're looking for is called DVD Catalyst, and you can find it here:
http://www.pocketdvd.ca
It specializes in turning dvd's into tiny files to fit any memory stick, but it can also create very high quality vids if you want - it's completely up to you.
I've tried a lot, and this program is by far the easiest and cheapest around - also received pocketpcmag.com's award for best ripping software.