it varies but as long as it is compatible with a 1000+ FSB, you ought to be good to go. thing with Conroe is, it is able to make efficient use of whatever mobo is out there for 975xx and 975xx chipsets so I imagine you can go with a trusted brand and check how it performs.
In light of Conroe coming out, AMD would be slashing prices pretty soon since Conroe is apparently in the hands of distributors right now. People can get a hold of Conroe chips as early as the second or third week of August, it seems.