Clearwire, Comcast and Sprint today announced plans to launch their respective WiMAX mobile services in several additional cities this summer. The rollout will focus heavily on Florida cities such as Daytona, Jacksonville, Orlando and Tampa. At the same time, the so-called 4G service will also launch in the previously-announced Kansas City, St. Louis and Salt Lake City, but major cities such as New York, San Francisco, and Washington, D.C. will still have to wait.

Clearwire has said it will cover 120 million people by the end of this year, and is spending more than $3 billion to roll out networks as fast as possible. The service provides about 3Mbps to 6Mbps in real-world downstream speeds and it's available from each of the aforementioned companies under their own brand -- Sprint 4G, Clearwire's CLEAR and Comcast High-Speed 2go which is sold as part of a Fast Pack that bundle wired Internet with wireless Internet. Time Warner will also market the product under Road Runner Mobile in other markets like Rochester and Syracuse.

Clearwire's 4G plans will have a major impact on its partner, Sprint. Unlike AT&T and Verizon, the carrier has thrown its weight behind the WiMAX variant of 4G, while its rivals are pushing Long Term Evolution (LTE). Sprint is rushing to implement the faster networks and plans to launch the first compatible smartphone, the HTC EVO 4G, later this year.