How do i jailbreak and unlock my iphone 3G for Tmobile?

i accidentally locked my iphone the other day as i updated it through itunes. Now it just says to insert a working sim. I cant get it to the homecreen. it just has a sign to connec tthe usb to itunes and it has the little message on it. ihave tried jailbreaking through the videos on youtube but nothing has worked so far. i m guessing that all the videos had iphones with the homescreen already showing up unlike mine and thats why its not working. can i get some help please? =(

I suggest you can use Jailbreakme.com/ to jailbreak your phone and the permanent remote unlock service from Prounlocking.com to unlock your iPhone 3G.