I've only just discovered
http://www.writingforums.org. It has a form on Reviewing -
http://www.writingforums.org/forumdisplay.php?f=71 - which also covers some critting issues.
I like
http://www.a-l-kennedy.co.uk/books.htm - it's A.L.Kennedy's opinions on how useful/good her reviewers/critters are.