There was a great deal of fanfare in late 2003 when the FCC freed up 255 MHz of spectrum in the 5 GHz range. The World Radiocommunication Congress 2003 (WRC-03) recommended making a single frequency band available worldwide, and adopted a resolution to make the 5.470-5.725 GHz frequency band available throughout the world for the use by wireless LANs. The WRC is an advisory body, and therefore an FCC decision was required to implement the recommendation and allocate the spectrum in the United States. I recently had to look up the actual text of the rule, and I had a hard time finding it. The rules were released on November 18 as part of FCC Report & Order 03-287. The text of the actual rules appears in Appendix B of the document. The core of the rules state that dynamic frequency selection (DFS) and transmit power control (TPC), as described by 802.11h for wireless LANs, are required to use the harmonized band. The report identifies existing services that might be affected, and discusses how 802.11 spectrum management services can mitigate negative effects.
Although the order is now over a year old, I do not know of any devices allowed to use the harmonized wireless LAN band in the United States. The reason is revealed in the order. Radio devices must be tested for compliance to FCC rules, and the test and certification procedures took quite some time to develop. (The proposed schedule is in Appendix D of the FCC report.) A final report was originally scheduled to be submitted to the National Telecommunications and Information Administration (NTIA) in January 2005, though I have not looked to see if that milestone was met.