You need to unlock, not jailbreaking. Going to refer you to wiki or blog.gizmoaccessories.com and search for "unlock" or "jailbreaking". The difference is important.

I think you can do it without activating...but check the blogosphere for step-by-step instructions. And if you are at firmware 3.1.3, you are screwed for now, until they figure out how to do it.

I was wondering if there was a way to skip the activation process and go strait into jailbreaking it to use on T-Moible? I've Had the IPhone just sitting here paid 450$ for it and i really want to use it plzzzz help