If you are already tired of waiting for a carrier unlock solution and want iOS 4.1 on your iPhone 4 right now, you can have it. There is a way to update your phone without updating the phones’s baseband along the way.
iClarified has a complete walkthrough for the update process. You need a regular iPhone 4.1 firmware, the application TinyUmbrella and iTunes. The method works on both Windows and Mac. Check the iClarified tutorial to see how it’s done.
When you’re finished, you can jailbreak your iPhone 4 running iOS 4.1 with either limera1n or greenpois0n and then you can unlock the regular way with ultrasn0w.