Over at Marvel(dot)com, Tom Brevoort's done several entries on his Blah, Blah, Blog focusing on the early development stages of Civil War.
If you've got an hour or so to kill (and hey, who doesn't, right?) head on over here for Mark Millar's initial CW pitch with Marvel EIC Joe Quesada and Brevoort himself providing feedback, and then here for the first couple pages of Millar's prototype script for #1.
I found it interesting how CW went from being a 12 issue maxi-series to a 7 issue mini, but still tried to shoehorn in most of the same beats.
Some interesting notes on Thor, the Hulk (seems WWH was supposed to end up happening in CW, becoming the event that reunites the heroes), Simon "Wonder Man" Williams' bid for Congress, and the eventual fate of Captain America.