Let me start by saying that if you write for children and you're not in SCBWI, you need to join. http://www.scbwi.org/
Through the Society of Children's Book Writers in Illlustrators, I have joined a critique group which has been very helpful.
I also posted a question about "Interior Monologue" (see previous post) on the SCBWI discussion boards. I got some amazing answers from expert writers.
Not to mention last weeks mini-conference about Social Networking.
Thanks to everyone who makes SCBWI possible.