Better yet, iTunes is configured by default to update your iPod with all of the songs in your music library. Plugging in your iPod will open iTunes, and the update will begin automatically. It's called "synching." I have an iPod and iTunes makes it very easy to manage your music on the device.
An iPod uses a USB 2.0 or Firewire connection. As long as you have one of these types of ports, then you're set. If you don't have these types of ports, then you will need to buy a USB 2.0 or Firewire PCI card.