If you have the Leadwell then it will have analogue input servos, you would have to get different drives to use withthe parallel port or SmoothStepper. However there is a motion controller called DSPMC that allows you to use analogue drives, it might be worth looking at that.
www.vitalsystem.com I have not used one but have heard good things about it and I believe it does Index homing as well
There is a guy on these forums that has done a Leadwell, he has a post in the Show and Tell part of the forum, his name here is fdos.
I have the ladder in the PLC to do the toolchange for the front toolpost and rear turret on my lathe. I also have a macro written so that when I call a certain tool the macro will send a signal to the PLC to index the turret/toolpost to the correct tool. Once it is there the PLC will send a signal back to Mach and the toolchange will be complete. This is all done over serial Modbus.
Hood