With the popularity of vintage elements in design, especially papers, I created a set of social networking icons that are free for personal and commercial use. The only limitation is that you can't claim them as your own or resell them. That's it. There are both color and neutral versions of each icon (works great for CSS sprites), and the icons include: Facebook, Twitter, Blogger, Digg, Pinterest, Google Plus, LinkedIn, Delicious, Technorati, Flickr, Instagram, StumbleUpon, RSS, Vimeo, Wordpress, and YouTube. All the icons come at 300 pixels wide, so that they can be reduced to whatever size you need. They are .png files on a transparent background.