While the sound level that comes from a speaker headset is not exceptional (as it is designed to be next to your ear), they still make for a good little speaker for an old iPod or mp3 player without its own speaker.
The speaker fits easily in your pocket and is a nice little companion for your iPod or mp3 player on those days out and about.
Step 1: Collect The Parts and Tools
1x Headset (I used one out of a phone headset which also had a microphone)
1x Film Canister
Dremel / rotary cutting tool (or you could use a hand saw if you have neither of the before mentioned)
Selleys Knead It multi-purpose putty (or similar) OR bluetak