Mini Headphone Splitter/Switch

I am looking for a compact two way mini headphone jack splitter that would allow me to direct audio output to one or the other sockets, probably via a switch. The reason I'm looking for this is I have a Mac Mini with only one mini jack for audio output. I would like to have my computer speaker system connected at the same time as my headphones and simply switch from one to the other. Anyone know of such a product or even a workaround?