old3eyes:

DrCheese: Just be aware that T-Mobile use 1700 and 2100 MHz for WCDMA so you might fall back to Edge or 2G if you are in a 1700 MHz area, unless your phone can handle that frequency. GPRS and Edge are on 850 and 1900 MHz.

David.

It's actually worse that that for T-Mobile 3G.  They use both 1700 and 2100 at the same time (AWS standard) . 1700 for send and 2100 for receive so you could very well be running GSM most of the time if your fone does not support AWS