guide for 3.1.2 unlock?

[g916]

Are there any simple guides around that will tell me how to unlock/ jailbreak my 2g iphone for t-mobile?
i found this youtube video [ame=http://www.youtube.com/watch?v=5uCPZgX1pY0]YouTube - Unlock & Jailbreak iPhone 2G on 3.1.2[/ame] but its kinda vague and it seems like i'd probably mess it up lol. Help is very much appreciated

[i.Annie]

1. upgrade to 3.1.2 through itunes.
2. download blackra1n
3. plug iphone into computer and run blackra1n
4. run blackra1n app and install Cydia and/or RockApp, and blacksn0w (unlock for 5.11.07)
5. exit app then re-run and select "delete blackra1n"
6. reboot
7. if you have any problems or questions feel free to ask.