I used to put my iPod into a plastic bag and secure the top with Sellotape or rubber band not to the iPod get wet, but it is kind of a bother and messy to take out the iPod out of the bag after I get out the bath.
So this idea came to me when I saw a small - almost the size of iPod - plastic zipper bag at a drugstore.
This is a extremely simple to make drip-proof iPod bag.
What you need is:
a small plastic zipper bag
a disposable stereo headphone (drip-proof one is perfect)