Answer: How does the electoral college work?

The best place to get information regarding the Electoral College is from the National Archives (NARA). The Office of the Federal Register coordinates the functions of the Electoral College on "behalf of the Archivist of the United States, the States, the Congress, and the American People."

The total number of electoral votes is 538, one for each of 435 members of the House of Representatives and 100 Senators; and 3 for the District of Columbia by virtue of the 23rd Amendment. Pennsylvania has 21 electoral votes. Every 10 years, armed with the population counts from the decennial census, each state must redraw its district lines (called "redistricting"), determining the number of members each state has in the House of Representatives and therefore the number of electoral votes of each state. As a side note, redistricting is a politically-charged and fascinating issue. You can find more about redistricting from the Center for Voting and Democracy, as well as the National Conference of State Legislatures. The Purdue University Library has links to most US State redistricting sites, and Google News lists the redistricting stories happening right now. Lastly -- or firstly! -- please visit your local library for the large number of books on redistricting.

Back to the question at hand. In all but 2 states, electoral votes are a winner-take-all affair. However, in Maine and Nebraska, "two electors are chosen at-large by state-wide popular vote and the rest are selected by the popular vote in each congressional district. As a result, the electoral procedure in these States permits a split slate of electors to be chosen." (from NARA).