Josh Heitzman reports that the September CTP of the Visual Studio 2005 SDK is now available for download by VSIP partners at http://www.vsipdev.com/downloads/. According to the download page:
The September CTP has added C++ Menus And Command sample, C# Services sample, C# Tool Window sample, the SDM SDK, C++ Package Reference and Updated Help Content.
If you aren’t familiar with the Visual Studio Industry Partner (VSIP) Program, details are here. Basically, it’s for ISV’s that want to integrate their tools with Visual Studio.