A Billion + Change
Pittsburgh Cares, a non-profit organization dedicated to helping other Pittsburgh non-profits find volunteers, and a client of mine (check out their Pittsburgh Cares Wishlist site, dedicated to helping non-profits in Pittsburgh find goods they need), clued me in on A Billion + Change. The goal of the website is to recruit professionals who are willing to provide pro-bono services to non-profits, and their goal is to reach $1Billion in pledged hours by 2013. I signed up, as I typically do one or two completely free projects a year (for organizations I really love, such as Bike Pittsburgh or Austin Yellow Bike).
If you provide a service, I highly recommend checking them out. You might even get a little additional exposure from it all!