I just got my N900 but am only getting 2.5g -- despite t-mobile's maps claiming I'm in a 3G area.

(Oh, and the mic works -- woohoo. I turned it on before charging)

My t-mobile sim was originally obtained in 2003 and I got the t-mobile vpn internet (internet3.voicestream.com) when it was GPRS only. When EDGE came out, I was fine when I upgraded to an N95.

Is there such a thing as a 3G SIM? Am I going to have to get a new one? (and a new plan) :-(