Huffer,
Think about it. 5.1 = 6 cables. (1)Left front; (2)right front; (3)center; (4)left surround; (5)right surround; (.1)subwoofer. 3 cables like the ones John linked, which are just two cables stuck together, 3x2 = 6 cables. 3 of any regular analog audio cables will work just fine.
If you'll look at your pre-amp and amp you'll see the multi-channel inputs and outputs are probably color coded (left=white; right=red) These cables typically have a red and a white connector, or a red and a black connector at each end (Red for right channel, white or black for left channel).
Most pre-amps and amps have the left front input/output(white) and right front input/output (red) beside each other; the left surround input/output (white) and right surround input/output (red) right next to each other; and the center and sub inputs/outputs (both probably black) right next to each other. So, 3 of those cords will work beautifully.
