I found the original tutorial on Photojojo. The directions are written out below with some of my own additions.
STEP 1: TRIM PAPER TO DESIRED SIZE
You can use a ruler and X-acto knife or a paper cutter. I just folded and tore the paper for rough edges.
STEP 2: GLUE STACK OF PAPER
Tap the stack on a hard surface so one edge of the stack is even. Apply a thick layer of glue to the even side and spread with your finger. Use the binder clips to hold the stack together. Let the glue dry for 15-20 minutes. Repeat this step at least one or two more times.
STEP 3: DECORATE YOUR COVER
For the covers of the notepad, you can use photos or cardstock. If you chose to create your own covers on cardstock like I did, now would be the perfect time to start drawing/decorating them. For some of the notepads, I used chipboard for the backing.
STEP 4: MAKE A PAPER SPINE
Cut a strip of paper that will fit the width of your notepad. This will be the length of the strip. The width of the strip can be determined by you. It just depends on how much of the spine you want to show on the front and back covers of the notepad.
STEP 5: GLUE STRIP AND COVER ONTO THE STACK
Place your cardstock or photo covers on the front and back of the paper stack. Spread a thin layer of glue all over one side of the paper strip (spine) with your finger. Glue the strip to the glued part of the paper stack then fold the strip over the front of the stack. Smooth the strip with your finger and repeat for the back cover.
STEP 6: LET IT DRY
Clamp the binder clips on the glued side of the notepad to dry. If you want your strip to look smooth once dry, place a stack of heavy books on the notepad.
This is a really simple project if you don't mind waiting.