This Nation
This nation.com: Electoral College
A textbook excerpt from ThisNation.com that includes a useful chart of electoral votes by state. Clickable links to pertinent articles and amendments of the Constitution are another plus.
Other
The u.s. Electoral College Calculator
Provides an overview of the electoral system and the process in which the president is elected. There is a visual calculator that lets you track election outcomes. Data for all U.S. elections is included.
New York Times
New York Times: Crossword Puzzle: The Electoral Process
Twice a month you can play a new crossword puzzle on The New York Times Learning Network. This one is called "The Electoral Process."