Up until now the only handsets that have supported both T-Mobile and AT&T 3G have been made by Nokia, which is a bit ironic since they have absolutely zero presence in North America. It’s expected that AT&T will be given the go ahead to swallow up T-Mobile this coming March, so these multiband 3G devices will be needed as AT&T restructures T-Mobile’s current network to better lineup with their plans for expansion. AT&T has said that they’ll use T-Mobile’s existing HSPA+ network to roll out LTE access and that at some point in the future T-Mobile customers will need to upgrade their handsets to something that’ll support their current high speed network, which operates in the 850 MHz and 1900 MHz bands.
http://www.intomobile.com/2011/07/10...fc-and-att-3g/