I'm about to get my first PB (and 3rd Mac - w00t!) to, erm, complement my other machines at home. Anyway, one of said other machines has a set of 5.1 Dolby surround speakers requiring 3 jacks in order to get full functionality. Does anyone have any suggestions for rigging anything up? I'm not adverse to purchasing a USB or other adapter if it will work. Thanks in advance!