There are 4 sets of original icons for pc with 4 different themes: video editing, 2001 a space odyssey, Fight Club and the new Zealand... have a good download!

Eight sets of most popular icons for software uses and fun icons for desktop personalization...

This set of free hand drawn doodle icons includes 14 graphics tailored specifically for bloggers. Including social media graphics for Delicious, Design Float, Digg, Facebook, StumbleUpon, Technorati and Twitter...

This is a website full of the free icons that are available from for Mac and Windows and they come in various sizes... and yes, they're all free!