Is the vice president always the same party as the president?

A presidential candidate is free to choose anyone he/she wants as a vice-presidential running mate. Realistically, though, the candidate chooses someone from their own party, since their chances of being elected with a running mate from a different party would be minimal.

Originally the VP was the candidate with the second greatest number of votes, essentially the one who lost the election. Now the VP is selected as a running mate. A presidential candidate decides who he/she thinks would provide a good "draw" to the voters.