National Marrow Donor Program
Provides marrow transplants from volunteer unrelated donors to patients with leukemia, aplastic anemia and other potentially life-threatening blood diseases. http://www.marrow.org/
GuideStar
Free service with information on the programs and finances of more than 600,000 American charities and nonprofit organizations, up-to-date news stories on philanthropy, and resources for donors and volunteers. http://www.guidestar.org/