Clearwire announced today it's adding more cities to its list of "who's getting 4G WiMax service next". They are: Miami, Pittsburgh, Los Angeles, Salt Lake City, Cincinnati, Cleveland and St. Louis.

This is in addition to New York City, Houston, Boston, Washington, D.C., Kansas City, Denver, Minneapolis and the San Francisco Bay Area, already slated for launch by the end of the year.

Clearwire claims it will be availabe to 120 million Americans by the end of the year.

4G promises to be as fast as typical DSL speeds. WiMax, unlike WiFi, provides a wireless connection for miles. In other words, with WiFi, you barely get a connection at the outside tables at Starbucks. With WiMax, you get a wireless connection all the way to the next Starbucks location.

Here's more details from Clearwire's announcement today:

1. 4G service will be available for the iPad through Clear Spot.

2. Dell is launching a 10 inch netbook that is 4G capable.

3. Clearwire will be making some serious upgrades to its back end technology to boost network speeds and dramatically increase network traffic capacity.