Are you sure that's not an amplifier? Speaker wire is used for amplified input or output while RCA lines are used for line level input or output.
Look for an RCA connection called "line in" and use a 1/8in(3.5mm) to RCA cable to connect your ipod to that connection. Sometimes DVD players have these. http://www.amazon.com/Hosa-Cable-CMR206-Stereo-Adapter/dp/B000068O33
Also its possible that there is a 1/8in input that you can plug you ipod directly into.