Both radioshack and Amazon had the Motorola HS820 on sale for 30 dollars this week. I bought one, popped it open. I wrote this up to show how easy it is and why you shouldn't be afraid.
Step 1: Remove the Ear Hook and screw
1) I'm not sure of the technical name, but I'm going to call it the ear hook as it hooks around your ear. It just pops right off if you give it a slight tug. It's supposed to pop off so you can change the orientation of the set. It turns out that I'm left earred.
2) After you remove the hook, then take out the screw. It's a hex screw but, I found a mini-flathead screwdriver that was able to fit perfectly.