Google Election Maps:

This Google page lets you see state-by-state breakdowns, with vote totals within each state, and also county-by-county breakdowns, if you click on the state and then click on "County Map" in the upper right-hand corner of the pop-up window.

If you have Google Earth installed, you can just go to this page and click on "Download Historical Voting Results" in the right sidebar. Thanks to Prof. Jim Gibson for the pointer.

Dave N (mail):
I looked at it and it is very cool--though be careful because it will really slow down your computer
11.3.2008 8:49pm
Asher (mail):
This site is better, it has county maps going back to 1960:
11.3.2008 9:32pm