* The American Presidency Project is mandatory reading for political science aficionados, bloggers, historians, journalists and curious bystanders. It has everything you want to know (and don't) about presidents, from Nixon's "Checker's Speech" on Sept. 23, 1952; to old presidential debates from 1960 and 1976 through this year; to day-to-day data on the current Gallup poll:
* If you are more of a visual person, check out all the presidential television ads from 1952 to today -- it's delighfully sickening -- online at http://www.livingroomcandidate.org/, which begins with a 1956 quote from Adlai Stevenson: "The idea that you can merchandise candidates for high office like breakfast cereal is the ultimate indignity to the democratic process."
No wonder Stevenson lost.
The most (in)famous, is LBJ's "Daisy Girl":
* Actual debate question from the 1960 Nixon-Kennedy debate.
* A cool feature from PBS, which will televise the Friday debate in Mississippi, is "Budget Hero":
PBS' "Vote 2008" site has more. Check the links, especially the "Interactive NewsHour/NPR 2008 Election Map."
* The New York Times also has a map. The best part is that you can speculate winners and make your own, like a fantasy sport.