Swapping SIM's - Can I give my girlfriend with a 3G my 3GS?

[dented42ford]

Basically, the title of the thread says it all.
I'm the proud new owner of an iPhone 4, and now have a slightly useless old 3GS. Is there an easy way to give my girlfriend, who has a 3G (my old one, in fact), my 3GS?

Basically, is it as easy as swapping SIM cards, or do I have to go to an AT&T store with her?

 

[izibo]

Basically, the title of the thread says it all.
I'm the proud new owner of an iPhone 4, and now have a slightly useless old 3GS. Is there an easy way to give my girlfriend, who has a 3G (my old one, in fact), my 3GS?

Basically, is it as easy as swapping SIM cards, or do I have to go to an AT&T store with her?

Easy as swapping SIM cards.

 

[JuNxXxReY]

Just a simple swap of SIM cards. No need to do anything else.