(Of course, if you don't have a guitar strap, it'll cost more than $3.00).
Step 1: Parts Needed
Picture 1: 1 1/4" screw with eye. I did have to hack it down some (with a dull saw, ugh) in order to get it to fit properly into the camera.
Picture 2: D-ring. I was originally going to thread the strap through the ring, but I didn't have an enclosed loop of nylon strap.
Picture 3: Guitar strap. In my case, I had my basses hanging from this strap. I took off my strap locks and I was all set. I figured if the strap could hold a 9lb bass, a DSLR would be no problem.
Step 2: Putting It Together
What's cool about this strap is the nylon webbing/shoulder pad. I wasn't so keen about it when playing bass, but for the camera, it's great. By adjusting the plastic buckle in the back, it keeps the shoulder pad in place when whipping the camera back and forth.
There you have it. Good luck and keep shooting!