I use a rigblaster NoMic, and got a cable from them to plug into the key jack in the rig. Very handy for contesting software. Also, K1EL just came out with a kit called WinKey, which will connect from the serial port of the computer to the rig. His site is www.k1el.com
I'm thinking of building it; I've built his K-20 keyboard keyer, and it's good quality. Hope this helps.