first generation and the iPhone 3G

What's changed between the first generation and the iPhone 3G?

Answer:

Not all that much. The iPhone 3G has all the features of the first one, plus faster 3G data downloads, GPS, and a better battery life. Externally, the phone's casing is slightly changed, with a thinner edge and thicker middle, but a flush headphone jack and solid-colored back make up the only other major differences visually. Everything else from the screen to the number of buttons and switches on the outside are the same.