The Fraternity of Shadows Library: A collection of netbooks and webzines for Ravenloft and Masque of the Red Death.
Talien's Tower Freebies Index: RPG Adaptations of movies (mostly for d20 Modern) by author Michael Tresca. Great material.
The SKETCH System Page: A page by Farsight games featuring (current ) 7 free small RPGs using their simple SKETCH System. Including unofficial Blade Runner, Highlander, and Star Wars games.
Horror Rules Script Archive: An archive of adventures for Horror Rules the B-Movie RPG by Crucifiction Games. Plenty of adventure ideas to steal.
Old Lord Skull: An repository of really cool netbooks and goodies for All Flesh Must be Eaten and other games. Definitely check out Alien Vs Predator- Duality. It's Aliens vs Predators vs Colonial Marines vs Zombies using AFMBE. It's pretty awesome.
And now, Christopher Walken wants to tell you a story...