If you have an older stereo system it might not have the right input. But newer ones likely have some auxiliary in that that's a similar plug to the plug on the BB. Basically both ends of the cord look the same.
Otherwise you'll need an adapter that takes the headset out on the BB to what sounds like RCA plugs on the back.
Something like this cord: 6 feet Stereo 3.5mm Y-RCA for iPod/MP3/PC
Although if you took pics of the back and front then posted it, someone should be able to figure out what it'll take.