Whats between the
iPhone 4 and iPhone 3gs ?
I wanna get one for free facebook but what can these iphones can/cannot do between each other ?
there is hardly any difference
Apple only makes new products mainly to prevent jailbreaking by upgrading the firmware and of course to make a profit
The 3GS is the older model. The iPhone 4 is newer and so is faster and has some unique features when compared to its predecessors.
There are a substantial number of differences between the iPhone 4 and iPhone 3GS in design, display, capability, performance, battery life and more.
For more details, an independent comparison also can be useful:
Hope this helps!