The simplest solution I used once, was a crude but functional wood bracket to hold the plunger end of a bulb release that had a 20 or 30 foot tube. The plunger tip (covered with some duct tape for protection) pressed against the camera shutter release.
A more flexible approach if you have a Canon digicam, is to load CHDK (search for that on wikipedia and google). The firmware temporarily loads on the camera and adds functions such as remote release when power appears on the USB connector. There are also scripts, such as bracketing, intervalometers, etc.
Haven't used it too much, but it does work on my SD800. And produces 10 bit RAW files.
Andy