

Maxim makes a chip that does exactly what you want. The MAX7219 drives 8
7 segment LED displays with full decode or drives 64 discrete LED's with
a 3 wire serial interface.  The chips can also be cascaded to allow very
large arrays.  I am working on a sign display using this part.

I'll have to post the contact info for Maxim later, it's at home.  There was
a series of articles on this chip in the last couple of Circuit Cellar Ink's.

Mike Harpe