Absolutely Theater: Forums dedicated to the discussion and operation of all things theater.
Community Theater Green Room: Discussion boards with topics including theater resources, articles, how-tos, directing, props, set design, play reading, and humor about acting.
Educational Theatre Association: Discussion boards relating to the theatre and acting. Topics include scripts, technical matters, performing arts education, and the theatre for life advocacy campaign.
Talk About Theater: Theater discussion forums include a variety of topics.
Theatre VOICE: Audio driven discussion forum in which theatre critics from across the UK press talk about London shows.