Arrrgh! Stereo closed-circuit mini jacks for Ruby?

[inverseroom]

I want to build a Ruby Amp with a mini-headphone jack that shuts off the speaker when you plug in.  I know they're out there (they're in cheap keyboards!), but I just searched Mouser online for like 30 minutes.  nothin'!  Anyone have a source?

And while you're at it, wiring instructions?  :oops:   I'd imagine I'd need some resistors in there, but damned if I know which ones and where...