checkmatechamp13 listed all the ones that are majority African-American. FWIW though, not all of those towns even as a majority necessarily represent the largest numbers of African-Americans in a community. For instance, Salem only has around 5,000 residents and Lawnside has only 2,700. So, even though African-Americans only make up around 6% of Cherry Hill, there are more African-Americans (4,360) in Cherry Hill then there are in Salem or Lawnside. Overall, Willingboro is the only major majority African-American community and there are almost as many African-Americans in Willingboro as there are in Camden and Trenton.
As for Willingboro, it is an interesting place. It was built as a Levittown in the 1950's and was of course segragated as the Levitt's would not sell to African-American families. A major in the US Army's Criminal Investigation Division applied to buy a home there in 1958 and was denied because he was African-American. He found out about an existing NJ law that barred segragation in housing if the project received federal funding. Since Levitt's mortgages were underwritten by FHA the segregation was illegal. The major sued and the case made its way to the NJ Supreme Court where the segregation was ruled unlawful. The first African-American family moved there in 1960 as a result of the ruling and was quickly followed by the major. This case was one of the foundational cases in the establishment of fair housing laws.
By the 1970's the name had been changed back to Willingboro (the original name of the area from colonial times) and there was an ever increasing percentage of African-Americans living there. This resulted in a lot of racial discord including the practice of "block busting" where realtors would go into an area and "warn" the white families that because there was an increasing number of African-Americans property values were dropping and they better sell and move to a "better" town. While they attempted to ban this practice, it certainly led to quite a bit of "white flight", primarily to the newer Burlington County suburbs being built out in Marlton and Mount Laurel.
Today Willingboro is an interesting place. There is a decent amount of crime (more than other suburban towns in the area, but nothing crazy) and drug activity (there have been a lot of dealers busted) there and the town certainly has a reputation locally of not being a great place. The schools are pretty poor especially compared to the excellent school districts in the immediate area. However, when you drive through it looks like a very nice, typical, suburban bedroom community. It's also not exactly dangerous, you can walk around there at night, but you do get a bit of a vibe.
These are pretty typical of the homes you'll see in Willingboro and it definitely has that "planned community" vibe with broad main boulevards and looping side streets with cul-de-sacs:
http://media.buyowner.com/pphoto/PHL/3590/1/full.jpg (broken link)