Cleoland
http://cleolinda.livejournal.com/2008/08/02/
A simultaneous analysis and love letter to the books.

Twilight Cliff Notes:
http://eborn6.blogspot.com/2009/04/twilight-cliff-notes.html
Super fast and snarky plot summary of the first book, with random family photos.

Stephanie Meyer
http://www.stepheniemeyer.com/twilightseries.html
The scoop from the author herself. Including the rough draft of Midnight Sun, Twilight re-written from Edward’s perspective.

Twilight Lexicon.
http://twilightlexicon.com/
Very thorough source on the books and movies, with chapter summaries, locations, characters, vampire mythology and more.