For those interested in delving a little deeper, here are some facts/tidbits:
The first black professional fraternity (Sigma Pi Phi) is also the first black Greek letter organization overall. The founder of Sigma Pi Phi later became a member of Alpha Phi Alpha. Other notable members of Sigma Pi Phi include WEB DuBois, Martin Luther King, Arthur Ashe, and Congressman John Lewis.
Lambda Phi Lambda is the oldest black arts fraternity we could discover. One of the founders is the band director at Ballou High School, which was the subject of a documentary which is available for free on Hulu:
http://www.balloumovie.com/
The National Sorority of Phi Delta Kappa, Inc., is not related (as far as we can find) to Phi Delta Kappa International, the professional association of educators.
Several organizations on the list may be inactive.