In a tweet sent yesterday, Musclenerd confirmed that tomorrow’s iOS 4 will be unlockable. Even better than that is the fact that the iPhone 4 itself will most likely be unlockable too.
Those of you on an iPhone 3GS with baseband 05.12.01 will now be able to unlock as well.
The Dev Team has been keeping this exploit secret for a while and saved it for the major update that iOS 4 is.