Dahon has a page that shows how one of their bikes can be adjusted for a comfort/upright position vs. aggressive/"sporty". It's not terribly technical, but for someone just getting into cycling, it has some nice profile pictures of how riders look with their bikes adjusted differently.

I imagine the same fit/position principles would apply to whatever type of bicycle a new cyclist would be looking for.

http://www.dahon.com/support/properfit.htm