Simple answer: yes
Less simple answer: Basically yes, it depends on your carrier.
Most eu carriers transmit 3G on 2100 umts (fine for at&t pre3) but a few also use 900 umts (which the at&t will not do). In the UK for instance, new legislation allows the 900 band to be used for 3G now and I think o2 (certainly) and vodafone (I'm not sure) have implemented it to increase the bandwith and coverage albeit only in the big cities so far.
So basically yes, you'll get 3g coverage on all major EU networks excepting that little bit extra on certain carriers
EDIT: check out this list, bearing in mind that the at&t phone won't use the 900 band
-- Sent from my Palm Pre3 using Forums