I am done writing my spec screenplay, now who do I send it to?

The first thing you need to do is send a copy of your script to the Writer's Guild of America, They charge a small fee to register it ( WGA.com) If you don't do this there is not a producer or company that will look at it. registering your script protects you from anyone stealing it, and it protects the film companies from being sued by you.

The next thing you need to do is get an agent that can represent you to movie companies. Without an agent, you don't stand a chance of getting it considered. You need to get the latest edition of of the Writers Market that lists agents in the US. Then you need to find an agent, who is accepting scripts from new writers. Next you need to know how to write a query letter to an agent. You can buy a book that tells you about the expect format and how to write a good letter.

You also need to be sure that your screenplay is formatted in the proper way. There are very ridgid rules about formatting a script, and you must not deviate from them. And of course you must know that you rarely provide information about camera angles, how to edit, music used and sound effects. Basically, you just provide the barebones story, and leave the rest up to the director.

So, it's not just a matter of writing a script and mailing it off to a studio. Making movies is a multu-billion dollar industry, and you have a lot of professional competition, and follow their rules.

You should have it copyrighted first, then start shopping it around to studios. No one can plagarize it, without your suing them, after it's copyrighted.