I need a device, dont know wether it exists or not but here it goes, im wondering if there is a device that is a dual plug that goes in your speaker jack and allows you to plug say maybe speakers and headphones into that jack but lets you switch from one to the other is there such thing?
-Chelski-
I dont think there is, there is one that lets you sue both at once 
My x-fi can do that, you plug your headphones in the front control panel and it turns the speakrs off.
Overclockers UK Forums - Can I put my speakers and a headset into my soundcard?
Check that thread over at overclockers, there is an image there, it lets you sue both at once, exept has no switch, thats what you wanted right? but with a switch.
Yeh
Theres this on the maplin site…
Multimedia Hub
It seems to be stereo.
Or get that lead off ebay, cut the wires and put switches on both lines. Or even a switch which accepts two inputs… That little box on maplin is probably the cheapest and tidiest way though.
EDIT: I cant get the link to work!
Here is the url anyway.
http://www.maplin.co.uk/Module.aspx?ModuleNo=34878&criteria=3.5mm%20switch&doy=25m11That link doesent seem to work :s
Edit* ah, just seen your edit