Blacksn0w/Blackra1n 3g with T-mobile

[agray92024]

Can some one post a tutorial about what to do step by step for those of us who are on t-mobile? I have a 3g operating 3.0 with tethering and when I watch the video for windows they say upgrade to 3.1.2 on iTunes and then proceed to jailbrake it with Blackra1n and then open it up on your phone and install Blacksn0w and it is then unlocked to work on any carrier. The question I have is 1) If I upgrade my firmware on iTunes want that make my phone unable to get on line so I can get the Blacksn0w from cydia. 2) Should I take the SIM card out first before upgrading firmware 3.1.2? I Really need some serious help before I do this. 3) What is the reason that everyone is upgrading to 3.1.2 is it that much better than 3.0?

[blkcadi]

Here is a complete step by step process.