WFF/WTB: 3.5mm to 3.5mm cable

monoprice $0.66 + shipping.

http://www.monoprice.com/products/subdepartment.asp?c_id=102&cp_id=10218

but I would recommend getting some sort of line out converter for your ipod for a lot better sound quality. something like this:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300208002066&ssPageName=MERC_VIC_ReBay_Pr4_PcY_BIN_Stores_IT&refitem=300207541604&itemcount=4&refwidgetloc=closed_view_item&usedrule1=CategoryProximity&refwidgettype=cross_promot_widget&_trksid=p284.m183&_trkparms=its%3DS%2BI%2BSS