Although you may not necessarily get professional critiques from a critique group of aspiring writers, many published authors belong to one or more critique groups and find their critique partners invaluable.
The majority of online critique groups are free–participants generally help each other by rotating submissions. Basically, this means you'll be expected to critique other writers' works in order to receive a critique of your work.
If you're looking for a professional critique of your story or manuscript, visit our professional critique links page.
If you are a writer looking to join a critique group, here are some resources to help you do so.
An free online networking site for children's writers to join a critique group–originally founded and moderated by Rate Your Story volunteer judge Terrie Hope.
Harold Underdown's Critique Group Webpage
Find an article written by Margot Finke on where to find critique groups (for children's writers).
Alexis Grant's Blog
An entire post is dedicated to how to find a critique group (she's a travel writer, but the article appeals to just about any type of writer).
The Writing & Critique Group Survival Guide
Written by Becky Levine, the book is available at Writer's Digest, IndieBound, Amazon, and more.
Rachelle Burk's Resources for Children's Writers
Section (10) refers to critique groups.