[DonRotolo]

These are very common 0.100" headers, widely available. You can use the female ends of the PWM cables, or buy connectors and make your own. For example, DigiKey sells Catalog No. SAM1121-11-ND (on Pg 128) which has 11 positions; we take these, cut them at positions 4 and 8 to make three 3-pole connectors (sacrificing those we cut). They are $2.12 each, or $18.97 for 10.

I know that Jameco also sells these, I believe at a much lower price.

They are also known as 2.54mm headers, and the males have 0.025" square pins. These can a;so be bought as blank plastic connectors, with the crimpable pins and sockets sold separately. As a crimper, you use the Radio Shack "RS-232 crimper" (about $13)