The political process in the US used to be based on a simple majority (when the country's population was much smaller), but is now based on an electoral college. Each state, depending on its population, has a specific number of "electors'; for instance, California, having a high population, has 55 electors where Alaska, having a lower population has only 3 electors (each state starts with a minimum of 3 electors, and is given more based on its overall population according to the census).
Dr Guy was mostly right. People cast their votes for the candidate of their choice and the one receiving a simple majority wins all the electoral votes in that state (which is why CA, FL, and TX are often so highly contested - check the 'electoral map' on Wiki to see). In December, after the results of the general election are generally beyond questioning, the electors for each state meet in DC and cast all of their votes for the candidate that the majority of the voters in their state selected. In order to win the election, a candidate needs 270 electoral votes.
There are caveats and 'what if' ideas that go along for the ride, but that's pretty much it in a nutshell.
