Atheist Alliance International as a group is legit, here is their page on Atheist Nexus http://www.atheistnexus.org/group/aai2008attendee…
Not sure about the guy who sent you the email though. He might be on their Atheist Nexus page.

I had been thinking of an idea I may want to discuss on the show if you guys would have me and I'm not too shy. Andrew and I had discussed me contributing soon after the show began but things have been pretty hectic my end.

People often state that increased emotional wellbeing is an advantage of their religion i.e. the oft heard 'it makes me feel good so I don't care if it's true or not'. I think there is an important flip side to that in terms of the mental/emotional distress religious dogma can cause and also the difficulty in identifying mental illness in a culture where talking to imaginary people is an accepted activity, or in helping people to distinguish between imagined things/delusions and real things in a world where relativism and tolerance is the dominant mode of discourse. These are themes that have been of importance in my personal life and in my work and I think they are important. What do you guys think?