Ultrasn0w 1.2 release for to announce our free carrier unlock for iPhone3G/3GS owners with a baseband later than 05.13.04 . There is same ready custom firmwares with 6.15.00 basebond . if you see iTunes 16XX error use iREB.
Links Updated . . .
Download Custom Firmware for Unlocking 06.15.00 Basebond iPhone 3G/3Gs
iPhone 3Gs iOS 4.1 (Unlock Factory) : Download
iPhone 3Gs iOS 4.1 (Lock Factory) : Download
iPhone 3G iOS 4.2.1 (Lock Factory) : Download