I found very useful links to find and download the social networking icons. In every website we required the social icons and vector images for using the site. I collected some we nice collection of social icons links.
1000 free social networking vector icons
There are indeed free high-quality icon sets. Through icons we can check the web designers and graphic artist’s skill.
http://sherifabdou.com/2009/03/60-free-vectors-icons-for-web-designers/
http://www.blogreign.com/2009/06/16-sets-amazing-social-networking-icons-free-download/
http://webtreats.mysitemyway.com/154-free-glassy-space-social-networking-icons/
http://sherifabdou.com/2009/03/60-free-vectors-icons-for-web-designers/
http://digg.com/design/Free_Social_Network_Icons
http://designreviver.com/freebies/6-free-new-social-icons-digg-twitter-stumble-rss-delicious-reddit/
http://www.komodomedia.com/blog/2009/06/social-network-icon-pack/
http://www.smashingmagazine.com/2008/03/06/35-really-incredible-free-icon-sets/
I searched for facebook, twitter, feedburner, digg.