50 of the Best Ever Web Development, Design and Application Icon Sets
http://speckyboy.com/2009/02/02/50-of-the-best-ever-web-development-desi...
http://speckyboy.com/2008/11/19/22-amazing-styles-of-rss-icons-free-for-...
http://speckyboy.com/2009/01/22/42-amazing-photoshop-and-illustrator-ico...

http://www.iconka.com/
http://www.iconarchive.com/
http://iconfactory.com/home

update 27.08.2009
http://365icon.com/