Gabriel's Angels- An organization in Arizona that provides pet therapy to "at-risk children, nurturing their emotional development and enhancing the quality of their lives forever." They currently have over 150 volunteers and deliver therapy to over 100 agencies. If you want to know if your pet is a good fit for their program, you can take a short survey on their website. The dogs must be predictable and able to handle hugs and have an affection for children.
http://www.gabrielsangels.org/index.php you can also check out their YouTube video @http://www.youtube.com/watch?v=YpCyEUdJQmI
Pet Partner Therapy Team is an organization that helps to bridge Therapy Dogs with the right volunteer location and support. You can check them out at http://www.petpartners.org/page.aspx?pid=183
You can also view http://www.therapydogs.com/ for an overview of Therapy Dogs.