Here are the most popular rumors about what iPhone 2.0 will be:

Support 3th generation networks (3G)
Apple will release a faster iPhone which will be able to work with mobile 3G networks.

Price
How much will iPhone 2.0 cost? The 32GB iPhone version will be $599 according to TG Daily. They also announce that 8GB iPhone 2.0 will not be over $399 and the 16GB - not over $499.

Size
Depth will be decreased to 2.5mm. The new iPhone will be as thin as iPod Touch.

New design
iPodObserver.com suppose that the new iPhone will have more plastic. The nickel-plated back will be replaced by a glazed plastic.

More current camera
In the new iPhone the 2mpx camera will be replaced by a 5mpx one.

Push E-Mail
Besides hardware changes there will be software changes too. The iPhone 2.0 will have a secured email client - push email supporting Exchange and Microsoft’s business servers.

Easy iPhone-to-iPhone communication
In the software of iPhone 2.0 will be included clients for fast messages between owners of iPhone 2.0.

GPS support
Greek website iPhoneHellas announce that basic feature of iPhone 2.0 will be bluetooth headset and GPS support.