This a variation on a folded paper CD/DVD sleeve I found somewhere on the internet. I made some additions and modifications to the folds and made it work for a standard letter size page.

Update:
Instructables user boyhowdy has made a perfect pdf template which clearly shows each fold and outlines the areas for cover artwork. Also, the template clarifies step 6 which may have been a bit cloudy to some. You can download the files below.

Thanks again boyhowdy, nice work.

Step 1: Start

Start with a standard letter size (8 1/2" x 11" sheet of paper. Fold diagonally across the long edge.

Step 2: After First Fold

This image shows the sleeve after the first fold. Now fold everything in half along the dotted line.

Step 3: Second Fold

After the second fold

Step 4: The Next Fold

Use a CD or DVD to get a rough idea for the next fold.

Step 5: The Third Fold

after the third fold

Step 6: Locking the Corner

take the two sides you just folded. open one side up a bit and insert the other part inside.

Step 7: After That

After locking th corner, place the CD in the slot to see the next fold.

Step 8: Fold Down

fold the top corner down over the cd and crease. You can angle it or leave it at a right angle.

Step 9: Tuck It

If you tuck the tab over the CD, it will lock it in place. if you've done it with it won't fall out. You can also tuck it behind the CD so you can see the labeling.

Step 10: Last Image

this show the sleeve with the tab tucked behind.
There are actually three little pockets you can put CD's in, each separated by paper. I've stuck as many as five CD's in one of these.