If your looking for a function in one application, there is a help menu, which lets you search for items that might be there.
The screen shot by apfhex shows you this.
Press CMD+ALT/OPTION+2 to open the equalizer, or go to iTunes > Menu Bar > Windows > Equalizer
Also check out this:
http://www.apple.com/findouthow/mac/
EDIT: something changed obviously while I wrote my post.