Sandcastle CTP can now be downloaded at http://www.microsoft.com/downloads/details.aspx?FamilyId=E82EA71D-DA89-42EE-A715-696E3A4873B2&displaylang=en

Instructions:

1. Visit the above link to download and install Sandcastle.
2. After installing Sandcastle, click here to create a sample CHM build.
 
Anand..