I found dozens and dozens of sites that had instructions for making your own flip book.  One of my favorites was done by reguitar squiggle, a young man who posted on YouTube.  He uses post-it notes to make his.
Here are some other links
WikiHow: Just the bare facts in text form, followed by another video which shows how to create a flipbook from loose paper.
Make: Bennett showed how he made a flipbook from some video he shot.
Fliptomania: Another informational site, with products for sale, including a flipbook “kit”.