Question about iPhone SIM

[tacofreak]

Hey guys,
I really want to buy an iphone and I have att and I have a razr with the 2 year contract,would it be possible to buy the iphone then put the SIM card from my razr into the iphone and it would work?

 

[TEG]

While the SIM card would work, you would still need to go through the iTunes Activation, which would either add the $20 iPhone data plan to your current contract, or just give you an iPhone plan comparable to what you currently have (whichever is cheaper), then restart your two-year contract with at&t. Once activate, you can take the SIM from the iPhone and use it in any at&t/Cingular or unlocked phone (to use as a backup).

TEG

 

[skubish]

My understanding is that the SIM in the iPhone will work in other phones but not vice versa. Unless of course, you unlock the iPhone.