Also called "Pace Counter beads", they're used to keep track of how far you've gone while doing land navigation. Great for Scouts, back-packers, people who like dangling bits of string with beads on it...
Step 1: What You Need
550 Cord: A staple of any soldier. I've heard it called "Parachute Cord" too. You can find a 50ft roll of it at any military surplus store for two or three dollars. You should be able to find it at a regular box store too.
Beads: Just about any type will do. I have yet to find the "official" shell-type beads anywhere, but it's not important; as long as they fit through the rope (some guys in my squad have cool-looking skull beads on theirs).
Matches: A lighter will work too. Anything that produces a small, fairly controlled flame. :)
Okay, now that you have that, let's get started!