Hi Mick
I use DSLRFocus for focus and shutter control, Hap Griffin cables (
http://www.hapg.org/astrocables.htm) for remote control. Long USB cable for up to 30 seconds and a Long Serial cable with LED's for long exposure.
DSLRFocus allows you to do 4 second real time focus shots on a small section of your shot and graphs the results to get your focus spot on. In Capture Mode you can setup how you want your sequence to run with how many shots, duration, ISO, time between etc you can setup an automated multi sequence if you like as well.
I am sure others will also comment.
JohnG