Brett Schulte has launched a Civil War blog and has enlisted some good help to co-blog with him, including author Eric Wittenberg and game designer Andrew Wagenhoffer.
It's a book-centric site; see in particular Wittenberg's extensive comments on Carharts Lost Triumph (he regards the core thesis of Stuart being synchronized with Pickett as bogus and he suggests the Custer material in the book may be dishonest, considering all sources).
And did you know that Eric Wittenberg is a Civil War publiher as well? Some great primary sources on his site.
Bookmark "Civil War Gaming and Reading." Hat tip to Brett Schulte for getting this together.