He's probably referring to the UserInterfaceIcons. If someone can provide a direct download link, please do. I want to use them but you will have to kill me before I install Zango.
For icons that require attribution (http://creativecommons.org/licenses/by/3.0/), what is the general practice for providing that? On each web page they're used, or do you put it on an 'About' page?