Dev Team: iPhone 3G/3GS On iOS 4.2.1 Unlock To Be Released By Sunday
A quick note for those keeping track, the iPhone Dev-Team has made very good progress lately on the iOS 4.2.1 unlock and according to MuscleNerd, an unlocking tool should be available by Sunday.
At this time, the unlock will only support iPhone 3G/3GS. The iPhone 4 unlock will require a bit more time.
From MuscleNerd:
Good progress today…everything is on track for updated ultrasn0w by Sunday/Funday at the latest (longer for iPhone4!)
Also keep in mind that to jailbreak your iOS 4.2.1 device will require a tethered jailbreak (reboot the iDevice and you have to use a computer to boot-up), so if you want the most optimal experience with your device, wait for a non-tethered jailbreak, then unlock the device.