Resize Your iTunes Window When It’s Too Big For Your Screen
Is your iTunes window so large that it takes up the full size of the screen and it’s still longer than the screen you’re viewing it on? Can you not grab the bottom right corner to resize it?
Hold the option key and hit the green “+” button to make it fit in the window.
(via http://forums.macworld.com/index.php?/topic/113130-itunes-screen-too-large/)