Can you play castlewars on an iphone?
Yes it is now possible to unlock all versions of iPhone 3G and 3GS
Is there any app for iPhone 4 that let you play backgammon iPhone vs iPhone?
Yes, Backgammon premium is the name of the app, from Trivial Technology. It's $1.99, it's worth it as most free options don't offer multi-player options.
IPhone how do i copy my play list to my iPhone?
Assuming your playlist is in iTunes, just go to your iDevice, and go to the Music tab. There you should be able to syncronise your playlists.
Can you play a song and play a game on the IPhone 4?
IPhone 3GS to iPhone 4. I just bought a iPhone 3GS the day before the iPhone 4 was announced. Is there any way I can return mine with the money going towards the iPhone 4?
I'm assuming this is old as the iPhone has been out awhile, but no there is no return policy with Apple or AT&T.