The iPhone and iPoid Touch are great for hand held gaming, although some games are quite hard to control on them if you want to play them for long periods of time, enter the iHandstick which is designed to make your iPhone and iPod gaming easier.
Your iPhone or iPod Touch snaps into the handheld grip, and it is compatible with the iPhone 3G, iPhone 3GS and iPod Touch 2nd and 3rd generation.
If you want one, the iHandstick is available for $16.99 from USB fever, I may have to get one to see if it improves my iPhone gaming, although I doubt it would improve it that much.
Gear Diary via Engadget