Resourceful hacker Eagleapex has swiped the innards of a hands-free headset -- or, more specifically, the 3/32-inch plug and its wire, which lets him plug into his Pentax DSLR. He tossed in a couple of buttons and a little switch, crammed it all into a 35mm film canister (oh the irony) and now he's got himself a cable shutter release for snapping long exposure HDR pics and the like without jostling the camera. He based the hack on a similar -- if fancier -- one for a Canon DSLR, which you might want to peep if your camera be of that breed.
Read - Pentax hack
Read - Canon hack