Need an icon? Need one for free? Check out The Noun Project, where designers submit icons and pictograms. It’s been live for a few years now, so they’ve accumulated a lot of icons. All in the public domain or with a creative commons license. Plus they are in hi-res vector format, so you can download and edit in illustrator if need be. Plus their store is really cool, where you can get a t-shirt or iphone case with your favorite icons. The blog isn’t bad either with the occasional design tip.