The iPhone Dev-Team has announced that they will be adding the iPhone 4 unlock to ultrasn0w and are in the process of fine tuning the payload to make it as quick to load as possible.
The team is also reminding users that there are alot of scammers trying to capitalize off their work. For your safety make sure you only install and run official applications (for which we will post links to). Also the Dev-Team does their work for free. So if you are being asked for money, you are being scammed.
Hopefully it won't be too much longer before the comex jailbreak is available after which the unlock can be applied.