1 Female RCA to Male 3.5mm Cable:http://www.amazon.com/gp/product/B0002J1LEI/ref=oh_o01_s00_i00_details
2 Male RCA to Female 3.5mm Adapters:http://www.amazon.com/gp/product/B002891YNI/ref=oh_o01_s00_i00_details
2 3.5mm Microphones:http://www.amazon.com/gp/product/B00284VD02/ref=oh_o03_s00_i00_details
As user Rogue Agent pointed out in the comments, you should take a look at the frequency range of the microphones you're buying. The ones I linked to are made for voice recording, so they aren't the best for recording music/sound. Human hearing range is about 20Hz - 20kHz, so microphones closer to that range would work better.