brucek is correct on both counts. However, I will add that if PC already has a MIDI port or "game port" (most likely as part of your sound card), you can use a cable like this:
midicable.jpg
My SB Live! card has the MIDI connection, and I had a MIDI cable, so I was all set. If you have to go out and buy one or the other, I think I would go with the USB to MIDI cable suggested by brucek, as it will be more portable. But if you already have the parts...