In the Sudan there is a group called the Janjaweed. It is a militia of Arab Muslims backed by the Sudanese government that attacks black villages, kills the males and sends females and children into slavery. Sudan has long been in a civil war between the Arab-Muslim government in the north and the Christian and animist blacks in the south as the Arab government has moved towards establishing shari'a.
I blogged about this earlier here.
This Website has tremendous detail and has followed the situation closely as the US seeks to put pressure on Sudan and acts more strongly than the usual mumbled pieties from the UN. And Nicholas Kristoff of the NY Times has chronicled this situation in his last four columns, the two most recent are free.