Decide what role you want philanthropy to play in your sorority experience. Depending on your availability, become a member of a social Greek organization with some volunteer opportunities, or a sorority with a service-only mission.
Contact your college or university's student life office, admissions representative or Panhellenic Council to see what groups are available. After you learn about the charities each one supports, match those interests with yours. For example, if you love children and your college offers only two service sorority choices, Chi Omega and Sigma Kappa, then Chi Omega's youth work is the better option for you than Sigma Kappa, which supports the elderly.
Explore the sorority's national website. National ones provide more information than chapter or campus sites with in-depth details about their mission, charitable endeavors and history.
Participate in a sorority's volunteer activity before you commit to a group. While service-only ones are more likely to offer this opportunity, it's also possible with social organizations as well, especially if the leaders know you might pledge. Unlike their members-only activities, sororities usually hold service work in conjunction with public events like a breast cancer awareness rally or Alzheimer's Memory Walk.