Screen Craft posted a helpful piece on writing an effective query letter to pitch your screenplay to an agent. I don’t have a lot of experience pitching screenplay agents, but I have a decade and a half of experience in querying literary agents. At the end of the day, they’re essentially the same. You have to be clear and concise while keeping the email short and alluring.
Check out Screen Craft’s Facebook page for more information about the screenplay writing process and upcoming contests for aspiring writers.