If you have ever dropped your favorite Toy, PDA, iPod, Zune, Mac book or Laptop in a puddle, you may have experienced the "blue smoke" scent that accompanies water damage when you went to turn it back on.
You can increase your personal electronics resistance to water with Silicone Spray. Used mostly for waterproofing tents silicone spray will help your electronics shed water, and dirt, and finger prints. Just give your device a light spray every so often, and then in a "safe" spot on the device drop a single drop of water to confirm that it "beads" like water does on a freshly waxed car. This will not make your device impervious to water but will make it safer if it gets wet or spilled on.
If you dropped your device in water and need to try and prevent the blue smoke escaping… before you turn the device back on remove the battery, and any power source, and submerge the device in electronics grade alcohol. This is alcohol that is 99% or better. Soak for a good 4 hours and then allow to air dry in safe place for 3-4 days. Do not do this anywhere near a heat source or flame. This alcohol is extremely dangerous follow the precautions on the container, and do not touch the alcohol as it will burn you.
This will not fix all devices but I have used this method on keyboard, cell phones, and TV remotes.