We first encountered this chip when working on the spokePOV kit. We wanted to control 60 LEDs from an Attiny2313. I only had maybe 5 pins to spare so even something like ‘charlie-plexing’ wouldn’t work. A great solution came to us with the suggestion of checking out the 74HC595. This is a chip that takes serial input (3 digital pins) and has 8 digital outputs. You can chain these puppies together to have near-infinite number of outputs. Perfect for controlling LED displays!
For an excellent tutorial on usage, check out the Arduino ShiftOut page
Pick these up from your favorite distributor, or from the adafruit shop!