Free to use.
Contains 20 icons for your website:
facebook, forrst (2 versions), twitter, deviantart, dribbble, ember, flickr, gowalla, last.fm, linkedin, posterous, myspace, skype, vimeo, picasa, open ID, tumblr, youtube, github.
Oh, right.. there is a bonus icon too
each in 3 colors (grayscale, color with white logo and color with black logo)
If you use them, credit me if possible. Also you can send me link to your work, I would like to see my icons in action