Wikipedia's Clearwire entry says at the top:
"Clearwire currently uses Expedience wireless technology, dubbed Pre-WiMax, transmitted from cell sites over licensed spectrum of 2.5-2.6 GHz in the U.S. and 3.5 GHz in Europe."
And Clearwire's site says that they are using OFDM ( http://en.wikipedia.org/wiki/OFDM
Motorola's Expedience overview is here:http://www.nextnetwireless.com/overview.asp
So it looks like it's something like WiMAX because it's using the same type of signal multiplexing method. As Wikipedia says, Expedience is something like "Pre-WiMAX.
As far as WiMAX being the 56k of the future - well, I'm sure that's what Intel is hoping for.