iPhone 4 (4th Generation)-Now Available!
–Unlockable with firmware 4.0 and 4.0.1 with modem firmware 01.59.00
iPhone 3GS (3rd Generation)
–Unlockable with firmware 4.0.1 and modem 05.11.07, 05.12.01, and now 05.13.04
iPhone 3G (2nd Generation)
–Unlockable with firmware (iOS) 4.0.1 and modem 05.11.07, 05.12.01, and now 05.13.04
iPhone 2G (1st Generation)
–Unlockable with firmware 3.1.3 and modem 04.05.04_G
How to determine your firmware and modem baseband
To check your iPhone’s firmware and modem firmware complete the following:
On the iPhone, go to Settings–>General–>About
Version=iPhone Firmware
Modem Firmware=Modem Firmware/Baseband