So you want to have to throw a switch to get one or the other? I dunno... mine is just a simple splitter. When I want to listen to my headphones I just turn my speakers off. But yeah, it looks like radio shack has what you want...
l2c
Edit: Actually, your search pulled up the wrong stuff... that's for TVs. I don't really know what Radio Shack's official name is for the product... you would be better off just going down there. I don't know about one with a switch, but is that really necessary?