Homeowner Tax credit ended 4/30. There was a mad rush in March and especially in Apr to have the contracts in place by the 4/30 deadline. All the contracts had to be closed by end of June (then, extended to end of Sept because of overload). I expect a slow rest of the year and early 2011.
The National Association of REALTORS research paper below graphs the the pending sales. These are the contracts in place but not closed . Look at the spike in Sept 09, and Mar/Apr 10, the 2 tax credit deadlines. Also note the drop in May, June.