It all depends on which digital bands it supports. If it strictly supports non-US digital bands then it won't work on the networks here in the US, unless it supports analog roam (which is rather rare for new(er) phones), and even then it would always be in roaming mode, really kill your battery, and analog networks are going dark in 2009 here in the US. If it's tri-band, depending on which band is missing, you could get rather poor or spotty coverage. If it's quad-band, you should be okay. As far as 3G, the European bands are totally different from the US bands so you will most likely not have any 3G support. Some of the really new/nice phones are getting US/European dual-band 3G support, but it's limited to just a few handsets at the moment.
