The : Guy : on : this : website : says
As soon as I get some more ambition, I'll post a quick schematic of how this is all hooked up, but rest assured, it's all very simple:

All LED anodes to one pin (TTL input type, NOT Schmidt trigger)

All LED cathodes to a schmidt trigger I/O port (i.e. on a PIC18F4620, PortD, PortC, some of PortA, etc.)
you can also try to follow the wires on his protoboard