Some of our favourite Documentary websites
http://www.hammertonail.com/category/archives/documentary/ (I really love this one, they do all films – festivals but have a doc section)
http://www.thedocumentaryblog.com/ (I like this one too!)
http://documentaries.about.com/ (rather US based)
Also, for watching docs, I go on festivalscope.com – it’s a paying website as of a month ago (70euros/year) but honestly, i went for it anyway. I keep up on new docs in festivals that way, and lots of fiction!
I am on the mailing list for a bunch of doc sites, but the notices I read most often are from Hot Docs or IDFA usually. We have a great online discussion group in Canada for doc filmmakers and I get a lot of doc news and topics through that.
Realscreen is good for keeping up to date, and they go to all the festivals so their site is good.
The former head Hot Docs programmer Sean Farnel has a good blog: http://rippingreality.com/ he knows everyone in documentary and goes everywhere!