Milt started a thread about choosing a cellphone. I think the title said something about ultimate cell phone plan. I posted my comparison of the two phones in that thread.
On your specific needs, I can't add anything about outlook sync. The iPhone 3G camera is crap, the 3GS is supposed to be much better, though still no flash - that's easy enough to test out in the store. Finally, viewing documents - what kind? PDF, Word, Excel, etc? I can try that out on my iPhone.
Edit - here
http://forums.pelicanparts.com/showthread.php?t=483328 I'll emphasize that, if a good hardware K/B is very important to you, the Pre is not your phone. It has a hardware K/B but not a good one.