New features of iPhone 4G:
Thinner! With shiny glass back piece - 9.3 mm thick.
Unified Mailbox (all email accounts in one area).
New wallpaper/background options.
A new, sleeker body design.
Multi-Tasking. (use multiple functions at once without going in and out of apps).
iChat camera (on the front so you can have video chat).
32G (basic) and 64G of memory. You're sure to never run out.
Extended battery life
Hi Definition Camera (5 megapixel) with a backside illuminated sensor AND FLASH
Hi Definition Camcorder.
Hi Definition audio.
True GPS built in.
(More information can be found at http://www.apple.com/iphone/design/index.html#design-video)