Jason,
for PC focus control you can buy commercial units from JMI:
http://www.jimsmobile.com/buy_motor_controls.htm
or from Orion version (Bintel has these):
http://content.telescope.com/rsc/img...Focus_revB.pdf
And to make the connection to the PC
http://www.store.shoestringastronomy...roducts_fc.htm
I'm sure you could also make your own using a stepper motor and USB interface kit (I think Jaycar has these type of things). I have both the JMI and Orion motors and can post some pics if you want.
Peter