True to its promise of bringing 42Mbps service to 150 million Americans by mid-year, T-Mobile will double its 4G speed in 56 additional markets today -- thereby surpassing its self-imposed goal (and leaving the door open for greater ambitions). Of course, the Category 20 Rocket 3.0 USB modem is currently the only way to experience this brisk performance, but the magenta-clad carrier seems intent to bring a 42Mbps HSDPA smartphone to ma
