I remember there was an ESPN article saying that 18 teams could be below the cap in the 2010.
Miami figure to be the biggest player in free agency (only Wade + options on Beasley+Cook+Chalmers on cap).
Here's a few of the main teams -- Cleveland, Chicago, Toronto, possibly Dallas and San Antonio. Sacramento are on the other end of the spectrum, but they figure to have cap space too. Also, Oklahoma, Minnesota, Memphis and Phoenix. The Clippers have some wiggle room but I don't think they have enough for a max contract.