Free critiques

First paragraphs are important!
The reason I mentioned online critique groups is critique is an essential part of writing a good story, IMHO. As editors, we would love to do back and forth interactions with authors and help them polish their stories. Unfortunately, time constraints just don't allow this. There are actually a lot of critique options out there in cyberland, some even free. For example, Critters Workshop is a well-known and well-respected on-line workshop/critique group for serious writers of Science Fiction, Fantasy, and Horror. I'd love to hear about experiences with Critters Workshop if anyone out there has any. :)
Writing World has a bunch of good articles and links related to critiquing. Again, comments welcome.
There's also Crapometer, a famous blog critique site.
I think at least one of the other editors has tried this. Comments anyone? :)