I hope you guys know(its ok if u don't cause now you will) that Gevey (Applenbery) just announced Gevey Ultra Untethered Unlock for iOS 5.1 iPhone 4 on latest base bands, I think including the one coming up(04.12.xx)....I would highly recommend it because its easier for everyone to use, and I want to stress please buy it from applenberry.com or their official distributors on eBay....because I have bought fake ones from my local china market and few other people claiming to sell authentic on eBay back when the first gevey came out and all I can say it "UNRELIABLE" now I have Gevey Ultra S running on one of my iPhone 4S and its amazing for $30....Goodluck to you all doing the SAM way but do note its a long process and it gets even longer as the next time you happen to travel abroad you gonna have to put your thinking cap on just to get that sim to catch signal compared to Gevey.
PS I am no way affiliated with Gevey, just trying to help those looking to explore the option of UNLOCKING while not permitted(due to contracts) or because of no available options.