Arduino powered 7 seg LED display using Shift Registers - I made it at TechShop

Step 2: Circuit

Now this can get a little dense and crazy if you're not careful so plan ahead and try to be as clean as possible. Not only do you have to keep track of which led goes where, you also have to keep track of how it interfaces with the shift registers. I used two colors for wiring so I knew which digit when where. Following the schematic and labeling your wires will be your best bet. Don't forget that because this is a common anode display all of the led's will be on when the IC sinks the current into them instead of being a source.