The next edition of the Biology Education Software FAQ (due out this
weekend) will have a listing for Braniac, which I thought was quite
good. While it doesn't have 3-d rotation, it does have a pretty nice
interface to a series of slices of the brain, plus views of the surface
and some other views. You can click on a part of the brain and it will
tell you the name of that structure. Check out their demo at
http://www.webcom.com/~medmult or write them at MedMult at AOL.com
They claim a mac version is coming soon, though currently they only
have windows.
Good luck,
Eli Meir
Dept of Zoology, Univ of Washington
meir at zoology.washington.edu