I thought alot of people might enjoy this read  http://www.amazon.com/Flat-Earth-History-Infamous-Idea/dp/0312382081.
I also liked some of the quotes from it like
"It is always good to question 'how we know what we know', but it is also good to have the ability to accept compelling evidence - such as the photographs of Earth from space."
she also makes a case that it is all but impossible to argue effectively with a "true believers". Which by going through these forums might be the most truthfull statement ever made on this website