I placed this already in the troubleshoot forum some time ago , but seems this is more the forum section for it.
Atm me and froyd (perhaps more people later on) are collecting issues and solutions for Zbrush 3, mostly stuff people have problems with when just starting with Zbrush 3.
We are putting it all on a site (dont mind the name , no redirect yet)
http://www.gamerauction.net/Zbrush3/
Hope it is of some use to some one.
Cheers
(if this is considered spam , please remove it)