Use at your own risk!
Just pick up a box of watertight zipper bags and double bag your capacitive device inside. The screen works perfectly through the plastic and the bags will keep your device dry. I wouldn’t recommend sustained completely submerged browsing, but this simple solution works great in the shower, or as protection in case you were to drop your device in the bath or pool. Also make sure not to expose the device to temperatures too hot for an extended period of time.
I’ve always wished that I had waterproof speakers to listen to music in the shower, but apparently all I need is a waterproof iPhone. You could set speakers up in the bathroom, hooked up to a netbook or UMPC, then use the Remote app on your iDevice to control iTunes and remotely control the music. See the waterproof bag in action: