Vincent, who happens to be the admin of TheiPhoneWiki, just confirmed that the unlock for all iPhone 4 basebands equal and above 02.10.04 is almost complete. It means that the upcoming version of Ultrasn0w will be able to unlock iPhone 4 baseband 02.10.04, 03.10.01 & 04.10.01.
UPDATE (FEB. 16, 2011) --> HOW TO PRESERVE YOUR BASEBAND.
Using Sn0wbreeze 2.2
Using PwnageTool 4.2