is the original iphone compatible with 3g? check out the description?

[maazarator96]

i have a tmobile samsung behold, i want to get an unlocked iphone which has 3g internet, i have 3g on my samsung behold so if i buy a normal iphone and stick my tmobile sim card in there, will the normal iphone have 3g or will i have to buy a 3G iphone?

 

[idunno298320948]

i have an original iphone, it is compatible with a 3g sim card but the phone itself will not access the 3g network.