If you want to write about Lovecraftian films, you should look at these articles:
"Lovecraft and Arrival: The Quiet Apocalypse"
"The Mouse in the Walls: Disney, Lovecraft, and Gravity Falls"
"Lovecraft Today: An Interview with S. T. Joshi"
"2001: A Lovecraftian Odyssey"
"The Haunter of the Dark: H. P. Lovecraft and Modern Horror Cinema"
"The Void: A Lovecraftian Analysis"
<em>The Lurker in the Lobby</em> should also be looked at.
There is a book on this subject. http://www.amazon.com/gp/product/1892389355?psc=1&redirect=true&ref_=ox_sc_sfl_title_2&smid=ATVPDKIKX0DER
I don't remember a ton about it, but I enjoyed Dark Waters quite a bit, though it's inspired by Lovecraft rather than based on his work. It's also quite slow and everyone I've recommended it to wasn't impressed. It's one of those films that is notable more for its atmosphere than for its strong plot, so be forewarned. Other than that, Stuart Gordon is pretty much the name you need to know.
Of those short films featured on the "H.P. Lovecraft Collection" DVDs, the only one I was impressed with was Cool Air. As mentioned, the Call of Cthulhu B&W silent film is pretty good, and apparently the same folks are working on my favorite Lovecraft story: Whisperer in the Darkness.
edit: I forgot, I actually own this book, which is a pretty good resource.