One of my favourite websites for resources, latest publishing news and webinars – http://www.cambridgeenglish.org/teaching-english/
I especially recommend to subscribe to their webinar alerts and get updates into your email account. Needless to say that the topics are varied and the speakers are excellent.
Another great thing is the free resources on all levels, ages and areas of interest – these include lesson plans, video materials, sample exam papers, etc., etc. Excellent IELTS resources, and straight from the horse’s mouth!
What are your favourite ESL websites?