T-Mobile USA activated HSPA+ with top theoretical downlink speeds of 42 Mbps in 50 markets across the U.S. This is double the top speed previously available from T-Mobile USA.

The launch includes major markets such as Atlanta, Chicago, Denver, Detroit, Dallas, Houston, Los Angeles, Miami, New Orleans, Phoenix, Pittsburgh, Portland, and San Francisco, among others.
T-Mobile’s first 42 Mbps-capable product is The Rocket 3.0 laptop stick, manufactured by ZTE.
http://www.tmobile.com