How to upgrade and unlock my iphone to 5.1.1 and preserve the baseband

Currently my iPhone is running on version 4.3.3 (8J2) and firmware 4.10.01. I'm using a Gevey sim, but I want to unlock my phone the software way, but I also want to update my phone to version 5.1.1- Can anyone help me please! I vote best answer. Additionally, can you attach a video with instructions if you know where one is online?

I know that the iPhone 5 is due for release very soon and if this is what you are after then I have found one of their "Test It Keep It" promotions - you simply use the phone for a few weeks - give some honest feedback and reviews and in return you get to keep the iPhone 5 for free - There are many different promotion companies online but this is the best one that I found…

Create custom firmware with redsn0w and then restore(hold Shift+Restore) in itunes to the new firmware. You may get some errors on the way, so just email me, if you do, there's a fix for each and every one of them.

You need call att to unlock it.