Michael Pavlovich has made some awesome videos, they are here:
I went, in 130 seconds, from knowing nothing about Live Booleans and not understanding anything in the documentation, to fully understanding them and finding them as awesome as advertised.
Check out his videos, he’s REALLY GOOD AT THIS!
A link to them ought to be stickied in this various places in this forum in my opinion.
Yeah really good info, i was just watching them.
i must give a big thank you to Michael. 
By the way, im new to Zbrush.
So… maybe its me but… This boolean thing looks like a BIG step for this program…
Such a huge world of new posibilities…
@Tukor:
Actually its been around for a long time in a couple of forms, but this new version is just exquisitely easy to use and far far more fun to work with.
What he shows in the first video alone leads to so many possibilities its stupefying, and hes got a whole pile more!