Should you be curious on how to control the viewing options for the new visualiser in iTunes 8, then wonder no more.
All you need to do is press ? when you have the visualiser running, and then the following shortcuts will work:
? – Toggle help screen
M – Change mode
P – Change palette
I – Display track info
C – Toggle auto-cycle (on by default)
F – Toggle Freeze mode
N – Toggle Nebula mode
L – Toggle Camera Lock