A few years ago I wrote a brief article explaining how to use Flickr images for free in your design work via the Create Commons License search feature on Flickr.
While I touched on the basics of Creative Commons licensing, I didn’t really go into any great detail. In this day and age, everyone has a digital camera – and everyone is sharing their photos. Without getting into the whole “you get what you pay for” argument, many designers are finding that not only is hiring a professional photographer not necessary for much of their work, but even using stock photography sites is less of a necessity nowadays. Photos using the Creative Commons license allow for personal and/or commercial use with little restriction. Not only that, but it’s a great way to gain exposure for your photo work.
Digital Photography School has a great intro to Creative Commons Licensing for photographers that covers the basics. For more detailed information, you can read the Creative Commons FAQ. You can also get a quick description of each license here.