Primates: Humans (Goog) 
http://anthro.palomar.edu/primate/prim_8.htm 

Human (Wiki) 
http://en.wikipedia.org/wiki/Human 

Human Evolution (Wiki) 
http://en.wikipedia.org/wiki/Human_evolution 

Agent Human 
http://www.agenthuman.com/product/table_of_contents.html   


Erectus Walks Amongst Us 
http://erectuswalksamongst.us   
Full length book available online for free.  Controversial but interesting.