hmm.. that's a tough one. I don't think that expensive cleaning products actually work, I'm very skeptical of those. Someone on another discussion board actually used toothpaste and it seemed to work for them. I wouldn't recommend that but I like the other suggestion which was to take it to a watch repair shop and see if they can buff out the scratches with something they may have there.
How can i remove scratches off my cell phone screen? - Yahoo! Answers
I'd definitely suggest getting some screen protectors now though.