I just wanted to pass along a link to Triggerstreet.com in case any writers (screenwriters or otherwise) have not heard about it... for some reason, it's tough to find on a Google search when looking for peer reviews:

Triggerstreet.com is a fantastic site to post your screenplays and other writings. It's a peer review site where you review randomly selected scripts and in turn, your script is randomly reviewed. There are a few other sites like Triggerstreet out there, but if you're looking for a wide variety of honest feedback (for free) this is the site.

Happy writing (and reviewing).