Microsoft, Google, Dell, HP, Intel, and Philips want underused, unused spectrum freed up: The six companies would like the FCC to approve technology for television channels that aren't in use in each market, opening hundred of megahertz to new purposes. Microsoft was to give the FCC a prototype device to day. Equipment could be on the market as soon as 2009.
An article at Marketwatch misstates what white space means, by the way. Unlicensed spectrum is unlicensed spectrum; white space is underutilized (or unused, depending on your orientation) parts of broadcast bands. You can read an analysis of what could be recovered at the New America Foundation.
Ultrawideband uses a kind of lowdown white space, or signals so low power that they sound like noise to licensed equipment.