just got some snap jacks from a company called zzyzx.
the short of it is this: it is a instrument cable with a magnetic connector on each end, similar to the magnetic power cable on the new macs.
they have built in some sort of circuit that prevents popping when you hook up your guitar to an amp and since the jack is a separate piece, if you trip over the cord it breaks free without ripping the jack out of your guitar.
it benefits my studio since i switch between instruments frequently.
i can just leave one of the jacks in each amp and in my preamp and switch between instruments and amps with a single cable.
i hate flash sites but the company has one for you to check out, if you can bear the long load time: zzyzx snap jack
they have a slightly less annoying page on myspace with a video about the snap jack.