My sister saw a set like these in a catalog for about 20 bucks. I'm cheap, so I didn't let her get them and made my own. The catalog is sold out now, anyway.
I should mention that this is my first Instructable, I'm new to the site.

Update June 21, 2007: I just found a great bracelet that would match nicely, courtesy of llama13, who I just noticed links to here. Thanks, llama13!

Another update, September 24, 2007: Make a processor belt buckle while you're at it! Wow, we're getting an entire wardrobe here! Who volunteers to make the IC chain mail?

Step 1: Collect Materials

The first step is to get all of your stuff. You will need:
Materials:
Circuit Board
Earring Hooks (two)
Jump Rings (I used four, but didn't decide to until later)

Tools:
Bandsaw (or similar device to cut the circuit board)
Needle nose pliers--it's waaaay easier if you have two pairs
Drill press with 1/16" bit
File or Sandpaper

Step 2: Cut the Board

Next you have to select an area of the board to use. It helps if you use a board with duplicate areas. I used an array of little surface mount components. I would recommend only using surface mount boards, as regular ones will be bulky. Keep an empty area towards the top to attach the hooks.
After selecting the area, cut out the board. I used a bandsaw with a wood blade because I'm too lazy to change blades. It didn't splinter, so I guess it worked. Test it on a scrap board. And of course, don't cut off any body parts. As my dad says, a blade can't cut you if your fingers aren't in front of it.

RaNDoMLeiGH brought up a good point that I hadn't thought of in the comments. Read her comment for a better description, but the basic point is, WEAR A DUST MASK! The dust produced by sawing through silicon can give you a huge assortment of unpleasant respiratory problems, namely lung cancer and silicosis. Wear a mask, use a saw with a vacuum setup, wet it down, whatever you need to do to avoid breathing the dust. It's a much bigger issue than solder. This goes for the next step, too.

Step 3: Smooth Edges

The bandsaw left a lot of rough edges, so I used some medium grit sandpaper to smooth them out. You might see little bits of copper traces sticking out; take them off. You can use sandpaper, a file, cheese grater (not recommended :-)) for this step. I tried a belt sander, but it didn't work.

Step 4: Drill Holes

Drill holes in the tops of the boards to attach the earring hardware. A 1/16" bit worked perfectly. Use a piece of scrap wood to support it, and go slowly to prevent splintering. Slow and steady wins the race.

Step 5: Add Hooks

Next, add the hooks. You will need two jump rings and a hook for each earring.
Use the pliers to open all four jump rings. Hook a ring through each earring's hole and squeeze it shut. Then, use the other jump rings to link the first rings and the hooks. Pay attention to direction so that the earrings hang right.
You will notice that in the images that one earring has two rings and the other only has one. I made the one-ring version first, but it hung sideways, so I added another ring to make them hang straight.

Step 6: Present

You are hopefully done! If not, run screaming around the block a couple of times. It won't help, but it will give your neighbors something to laugh at.
Congratulations! You have just saved about $19.89!