http://kenlevine.blogspot.com/
Ken Levine, writer on Cheers and The Simpsons. One of the old-school, lemmee tell you about my agent, grizzled old LA comedy-writing warhorses. Always great and he often does 'joke contests' on there, giving you a chance to impress someone who's written dialogue for Milhouse.
Phill Barron's, obviously *cough*.
And this, if you're a fan of writer's jargon like 'the bicycle joke' 'hanging a lantern on it' and 'placeholder' (as referenced in Arrested Development: 'I'll ruin your bicycle like a placeholder')
p://kfmonkey.blogspot.com/2005/04/writing-jargon-preservation.html
EDIT: (that blog is confusingly designed but there are 4 pages of jargon preservation, I found it easiest to find use the search function as there's no direct link. Read the user comments too, lots of people adding their own).