This PDF document from the St. Louis Community College lists service learning opportunities throughout the St. Louis region. Link from alphabetical, subject, and geographic location lists to the pages describing each agency, contact information, volunteer duties, training, skills or background check requirements and number of service hours expected from volunteers.
Founded by philosopher Peter Singer, The Life You Can Save is "a movement of people fighting extreme poverty. We hold that an ethical life involves using some of our wealth and resources to save and improve the lives of those less fortunate than us." (from About Us)