2 Computers, 1 set of speakers - audio switch?

Hi guys,

Here's my problem.

I have a desktop computer and a laptop computer. Both of them are sitting side-by-side. I've got a decent set of speakers connected to my dekstop that I'm quite happy with. The sound quality on my laptop is rather poor. I'd like to connect both of them to the same speaker system.

Now I've heard about KVM switches allowing users to swap between different computers while sharing the same monitor. I was wondering if there was such a device similar to this but for audio switching.

Also, is it possible for both the computer and laptop to be sending audio to the speakers at the same time? for example, I could be playing a game with sound effects on, but on my laptop i play a song. would the speaker system be able to play audio from two sources at once like this?

Any help on the subject would be a big help. Thanks very much in advance for reading this and for any help provided.