Naturally Apple's choice of optical audio-out cable is going to be a pain. Obviously, its not going to be one I'd just have around, that is not the Apple way! Rather than pay $30 plus at an Apple store or hifi audio boutique, this $6 cable does just fine for me.
If you want to use an Apple laptop or Airport Express as a streaming audio source, this cable will come in handy.
Monoprice 3-Feet Optical TosLink to Mini TosLink M/M 5.0mm OD Molded Cable via Amazon