Here are some anti-slavery organizations:
http://www.antislavery.org/
http://www.freetheslaves.net/
http://www.interpol.int/Public/THB/
Slavery is still prevelant in the world. There are approximately 25 million people involved in various form of slavery, from debt bondage to human traficking.
Sudan is the one country which needs more attention from the world. Beside the massacre in Dafur, the slavery situation there is perhaps one of the worst in the world.