Folks there is some bad news for the people out there that have iPhone 4 but with a baseband other than the 01.59.00. As @MuscleNerd from iPhone Dev Team has mentioned that unlock for the iPhone 4 that have different baseband than 01.59 is taking longer than expected. So unfortunately it might take a while before such an unlock will see the light of the day.
Here is the actual tweet by him:

In case you are on the baseband 01.59.00 you can still unlock using UltraSn0w.
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