Swimming for 30min-2hrs at my local health club is fun, but music definitely helps! I didn't want to pay $150 for a waterproof mp3 player so here's my solution for under $15 (I already own an ipod though).
You will need:
1) iPod shuffle or any small mp3 player
2) WATERPROOF headphones. I paid $11 on Amazon
3) Small party balloon (a dozen costs $1 at most stores)
5) goggles and swimming cap
DISCLAIMER: Try at your own risk. Mine works great, but I cannot be responsible for your ipod. Use a NEW balloon before each workout.
Step 1: Insert iPod in balloon
Insert iPod in balloon. I found that tucking the round end of balloon under the iPod clip helps keep it neat. It also gives you the option of using the clip, even though I don't use it.
Step 2: Insert headphone cord inside balloon
It is important that you only use WATERPROOF headphones. Coil up headphone cord neatly, attach it to iPod, then insert inside balloon. Leave about 12" of cord exposed with the ear pieces.
Step 3: Seal balloon opening
Tightly twist balloon end around cord as shown. Then tightly wrap rubberband SEVERAL times around balloon/cord, making watertight seal. Wrap extra rubberband around iPod and secure cord.
Step 4: Check before using, then go swim!
Double check balloon for possible tears before going into pool. Always use a NEW balloon each time because the chlorine degrades latex, and You need to charge your iPod anyway.
This is what it looks like installed under my swim cap. I have to turn it on before I swim, but I can control the song shuffling during swim. Putting one or both of my goggle straps under the iPod helps secure it fine.