Question about frequencies. I apologize if this has been asked before.

Hi gahook, and welcome to AF

You are correct that there are two frequency bands used for 3G in Europe. 2100 is the commonest - everywhere I can think of uses that. There are some networks in some countries which also use part of the 900 band for 3G - the main use of that band is still GSM (2G). In either case uplink and downlink are within the same band - there's no network that uses say 900 for uplink and 2100 for downlink, the way T-Mobile in the States splits uplink and downlink between bands.

So if you have 2100 MHz 3G you'll be fine. If you have 900 MHz 3G too then that's a bonus, but whether it will make a difference depends on where you are. You will also want GSM in 900+1800 bans for 2G coverage, but quad-band GSM is very common so that shouldn't be hard.

Do note that the fact that a handset has 900 MHz GSM does not mean that it can use the 900 MHz band for 3G, since those are separate systems.