im new at this so please cut me some slack.

i just bought a new iphone about three days ago so im assuming it has the 1.1.2 firmware. is that right? i can't affort the a t and t service so i need to know if there a way to bypass having to activate it. if i do, will everything work fine? also, if i decide to pay for a t and t, is there a way to relock it back to how it was when i got it so that i can activate it the way you are supposed to? will revirginizer do this? anyone have a link? i searched but got nothing. thank you.
ps i have a pc.