I subscribed to hcdOnline - will see how it works out. So far, I'm impressed. I bought the Representation book, but found out it's bad to go to agents without first having interest from a prodco.
I've heard mixed reviews of scriptpimp, and I entered the contest. Like Inktip they're very good at taking your money and convincing you they're looking out for you but are they really? HCDOnline is more straightforward - you go into the list, go through every prodco and find out what kind of movies they produce, who the development exec is, and who to call or send a query to. Links too!
Mandy is a free service that does this too, and you can search by region should you be an East coaster like me. I'm using this to search for reader jobs, and hcdOnline for query letters (just to stay organized). Well, we'll see if it's worth $200 a year or not.