If you have the Euro-Asian version (the one that supports the 900/2100 bands for 3G), then it will not work on AT&T's 3G. It's basically an 2G/EDGE only phone. As to bands, all generations of cellular technology (e.g., 1G, 2G, 3G, and 4G) have bands, because they all use antennas. With AT&T, your phone must support the 850MHz and 1900MHz bands for 2G and 3G to be fully compatible.

I bought a nokia 5800 XM from Iran (it was 20 dollars cheaper and it had some languages that I didn't ever see on Nokias from the US.

Anyways,

I come back to the US and I hear things about no 3G but don't worry about it until it dawns on me that it wont get off "E" (Edge.. I'm on AT&T). Did I screw myself over because the US doesn't use the bands 900/2100?

I just found out that 3G has bands.. i used to think it was either 3G or no 3G..didn't know about dumb bands

Thanks guys