Soon, the Visual Studio 2005 Team Suite August CTP will be available for download. You need not look for a Team Foundation Server August CTP, because there isn’t one. To put it simply, the Team Suite August CTP doesn’t have a paired Team Foundation Server. In other words - if you want to use Team Suite August CTP, you won't be able to use it with any Team Foundation Server. The next release of Team Foundation Server will be Beta 3.
[Update] Some people have noticed there's an item listed as Team Foundation Server in the August CTP folder. This file (en_vs2005_DTE_ctp_Aug2005.iso ISO-9660 CD Image) is actually Team Test Load Agent and Controller.