Can an Iphone 4 be used on any carrier?

I originally had an iphone 4 registered with AT&T but now I have verizon and just an unregestiered iphone 4. Can I hook it up with verizon and get all my information transferred from my current phone to my iphone 4?

No a AT&T iPhone is only able to be used on t-mobile or a foreign carrier.AT&T iPhone and sprint iPhones are completely incompatible