At first I thought this was a joke but it apparently isn't:
Diphalia is the medical term for having 2 penises.
Follow the link for a Q&A with a guy who has indeed two. It's also quite funny.
http://www.reddit.com/r/IAmA/comments/1u75hh/i_am_the_guy_with_two_penises_ama/
There are pics of they guy's phalli available but since they're obviously very NSFW I can't post them here.