EV-DO is being deployed nationwide by Alltel, Sprint, and Verizon. Not sure if that's the same as what you're talking about. EV-DO offers speeds of up to 2.4Mbps. 1xRTT offers speeds up to 144Kbps. Both are based on the CDMA architecture.
I am still not convinced that there is a true 3G cell network in the US, at least not like there is Japan.
For those that don't know what UMTS is, look here:
http://tinyurl.com/9p5b3