Assuming that it has regular RCA input connections, you will need an adapter to convert RCA to 3.5mm mini-jack
On this converter, the RCA ends (left and right) should be Male while the 3.5mm mini-jack end should be female
You will also need a cable with a male mini-jack on both ends. The length of this will depend on the distance between your laptop and the stereo.
Just plug it all in and select that input on the receiver.
If it has a Optical input, then an optical cable between the laptop and the receiver is all you need. Once again, select that port on the receiver.
Take a look at monoprice.com for all these cables and converters
The Apple specs state that we have a "combined optical digital output/headphone out (minijack)" on the side, and we would like to connect our mbp to our stereo receiver so we can play music through our (new) ceiling speakers. We would appreciate any help from anyone who has actually done this and knows the best method. If you could also please include the name(s) of any hardware/cables that should be used, we would appreciate that as well. Thank you.