unlock your 3G iphone free

Great news, it is now possible to unlock your 3G iphone without the need for an "Unlock SIM". The solution has been released from the iPhone dev team and its FREE. Their unlock Software is called YellowSn0w (YellowSnow) and it supports all software versions up to and including 2.2. You can read their blog HERE
Read a great tutorial on how to unlock your 3G iphone for FREE at iClarified here
I have tested this personally on my own O2 UK 3G iPhone and it works great!
Note: The latest software version for the 3G iPhone is 2.2.1. It is not currently supported by YellowSn0w. But rumors have it that a new version of yellowSn0w is about to be released (version 0.98) which will work with 2.2.1. Keep an eye on the dev team blog for updates.
If you are already running version 2.2.1 and want to unlock it, then for now you will have to wait for YellowSn0w 0.98 to be released. Some "Unlock SIM's" do claim to work with 2.2.1 but i have heard mixed reports on their reliability (read tutorial below for more information on unlock SIM's).
UPDATE: There is no news from the iPhone Dev team yet about unlocking version 2.2.1. So unlock SIM's are currently the only solution for this version. Please read my tutorial below for more details. Hopefully they will crack it soon....
If you have any questions about iPhone unlocking please post them in my new support forum here.