My favorite site for icons is Iconomize.com because the icon you choose automatically installs to your desktop with the shortcut already set. They have the facebook icon here, www.iconomize.com/desktopshortcuts/facebook-icon-installer/ Just click to install and it goes right on the desktop.

Yes! There are a lot of them out there. Here's a link to some on DeviantArt.

www.deviantart.com/#catpath=customization/icons/os&...ook

Make sure you look under the titles and make sure you're downloading the set for your computer's operating system (windows/mac/linux). :)