Spirit and Activation

[Dors]

Hi guys. I bought an at&t 3gs iphone(3.1.3). I dont have the sim with me to activate it.
My questions are?
1)If somebody activate the iphone for me in order to use spirit, the next time i reboot it will i need the sim?
2)If i get an at&t when i connect to itunes it ask me for some info like zip code, can i put any number in order to make it boot_
3)if i buy a prepaid at&t sim do i have to submit some info to itunes too?
4)Is there another way to activate it without at&t sim?

Thanks

Sorry for the questions but i am rly new.