This will show you how to get a cool itunes ‘now playing’ notification in your dock

open terminal.app
type:

defaults write com.apple.dock itunes-notifications -bool TRUE
killall -9 Dock

this will enable the setting and the next time you play something in itunes it will show you with a neat popup above your itunes icon!

to disable it

defaults write com.apple.dock itunes-notifications -bool FALSE
killall -9 Dock