freitasm:sbiddle: There are 9 ratified UMTS bands however the most common are at 2100Mhz (what we use in NZ and Europe) and at 850Mhz which is used in the USA and shortly in Australia by Telstra.
I think USA/Canada uses 1700MHz, while everyone else uses 2100MHz. 850MHz will be deployed in Australia, but it's not in use anywhere else yet.
Cingular in the US is building an 850Mhz network with Nortel and Lucent (hence Lucents calls for TCNZ to build a WCDMA network)