Can I Buy a Prepaid SIM Card Out in the States?

[realph]

I'm going out to the States (New York) in September for two weeks and plan to bring along my iPhone 4. Since I'd like to use the phone and not render it useless I'd like to know if I'll be able to buy a prepaid SIM out there and use all the phones capabilities, 3G included?

I don't trust using my carriers SIM (O2) overseas, too scared to come back to a huge bill.

Thanks in advance.

 

[eastercat]

Use the search function. This has been covered to infinity.