I've been using a ScotchBrite "High Performance Cleaning Cloth" (3M) for lots of delicate stuff (plastic eyeglass lenses camera lenses, digicam monitors, CRT screens, laptop screens, and ... my Pronto).
It just sucks fingerprints right off - sort of like those cloths you can get in a camera shop, only lots better. They're under $10 for the large ones 10" x 10" or so. I can't find the small ones in the Boston area but I guess it's not a big issue for the dollar or three I'd save.
Hoping this helps somebody...

I use the Fellowes WriteRights Screen protector overlays: [Link: fellowes.com] The ones that fit the Philips Nino PDA just needs about 1/8th inch trimmed off the length then it fits perfectly. It protects the screen from scratches, reduces glare, and I don't have to worry as much about what I use to clean the screen with.

Bob V.