T-Mobile has just announced it has increased the speed of its ‘4G’ wireless data network to a theoretical 42 megabits per second (Mbps) in 55 U.S. markets.  While this doesn’t mean much for smartphone users just yet, it is great news for laptop users who want faster internet access on their mobile PCs. 

To go with the new data transfer speeds, T-Mobile is also launching a new 4G USB modem, the ZTE Rocket 3.0, which will go on sale tomorrow for $99 with a two-year contract (after a $50 mail-in rebate), $199 sans contract. 

Smartphones with support for the new network speeds are certainly coming, though we don’t know anything definite on that point just yet.  Stay tuned.  It also should be noted that a “theoretical speed” is just that; real-world speeds will be slower, but we’ll have to wait to see just how much slower once the devices launch.

We’ve posted a list of the locations where the new data speeds are available after the jump.

Albany, GA, Athens, GA, Auburn, AL, Augusta, GA, Austin, TX, Bentonville, AK, Boulder, CO, Chattanooga, TN, Chicago, IL, Dallas, TX, Deltona-Daytona Beach-Ormond Beach, FL, Denver, CO, Detroit, MI, Durham, NC, El Paso, TX, Fort Collins, CO, Gainesville, FL, Gainesville, GA, Greeley, CO, Honolulu, HI, Houston, TX, Jacksonville, FL, Long Island, NY, Los Angeles, CA, Long Beach, CA, Santa Ana, CA, Macon, GA, Mayaguez, Puerto Rico, Miami, FL, New Orleans, LA, Oklahoma City, OK, Olympia, WA, Omaha, NE, Oxnard, CA, Thousand Oaks, CA, Ventura, CA, Phoenix, AZ, Pittsburgh, PA, Ponce, Puerto Rico, Portland, OR, Salinas, CA, San Francisco, CA, Oakland, CA, Fremont, CA, San Jose, CA, Sunnyvale, CA, Santa Clara, CA, San Juan, Puerto Rico, Santa Cruz, CA, Watsonville, CA, Santa Rosa, CA, Petaluma, CA, Savannah, CA, Seattle, WA, Spokane, WA, Tampa, FL, Tulsa, OK, Valdosta, GA, Vellejo, CA, Fairfield, CA, Warner Robins, GA, Wichita, KS.