Here are some companies offering Genetic Genealogy testing. Be sure to look at what each company offers.

http://www.africanancestry.com/
This company has a database of African population groups against which to compare YOUR dna to tell you a specific tribal group or groups you may match.

http://www.tracegenetics.com/ {specialty is Native American Ancestry}

http://www.ancestrybydna.com/ {This test tells you what percent of 4 different ancestries you may be, European, SubSaharan African, Asian, Native American, but does not identify a location}

http://www.familytreedna.com

There are other companies also.