I may not be smart enough to use HgSccPackage. :(
I ran through the installer, then from the View/Toolbars menu in VS2008 I selected "Mercurial Source Control Toolbar".
This was the result: http://h.imagehost.org/0215/HgSccPackage.png
Nothing seems to happen when I change and save any of the files within my project. The toolbar remains greyed out. I don't know of anything else I need to do to make this work, and have been unable to locate any docs.
Cheers for any help you can provide!