Today Sprint announced a major planned expansion of its WiMax-powered 4G footprint. Atlanta, Charlotte, Chicago, Dallas, Ft. Worth, Honolulu, Las Vegas, Philadelphia, Portland and Seattle will all see service launched some time during 2009. Sprint also said that it plans to launch WiMax service in Boston, Houston, New York, San Francisco and Washington, D.C. during 2010. In addition to the new markets, Sprint plans to offer new devices this year, including a single-mode 4G data card, embedded laptops, a broadband modem and a tri-mode phone. For the moment, Sprint’s WiMax service is still only available in Baltimore. Sprint didn’t say exactly when these additional markets will go live.