In support of 'Out-of-Africa' theory:
http://news.bbc.co.uk/1/hi/sci/tech/1323485.stm http://dsc.discovery.com/news/briefs/20020225/eve.html (this one addresses the mitochondrial DNA link alluded to in the previous one)
This paper considers the two (single-origin vs. multiregionalism) citing the points and shortcomings of both:
http://www.micro.utexas.edu/courses/mcmurr...llysherard.html
I haven't done much reading on the subject, but I'll come back to this one.