"The founders of the nation devised the Electoral College system as part of their plan to share power between the States and the national government. Under the Federal system adopted in the Constitution, the nation-wide popular vote has no legal significance. As a result, it is possible that the electoral votes awarded on the basis of State elections could produce a different result than the nation-wide popular vote. Nevertheless, the individual citizen's vote is important to the outcome of each State election." From The Electoral College Homepage FAQ section.

This is a pretty easy explanation of The Electoral College (although, I have to say, I had to read it about five times even though it's a grade 6-8 level).