David Lane is a playwright, dramaturg, workshop leader, unfeasibly lovely man, and one of my tutors during my MA at Goldsmiths. He also operates the Lane's List series of e-mails which really are one of the most astonishingly comprehensive and TOTALLY FREE resources on the Internet for writers of all ages and experiences. Every week, David pulls together lots of writing opportunities, competitions, submission dates, articles, blogs and other sundry resources, puts them together into a handy-dandy list, and sends it out to everybody who's signed up for it, at no charge, and purely because he enjoys doing so. David Lane remains my number one argument for believing in altruism.
You can read more about Lane's List - and sign up to it - on his website. If you're a playwright (amateur, professional, semi-professional) you've no excuse not to.