Huge collection of free screenplays.
http://www.imsdb.com
BBC Writer's Room
Advice from the BBC on writing for film, TV sitcom, TV drama, short film, radio sitcom, radio drama, and more.
http://www.bbc.co.uk/writersroom/writing/tips.shtml
Screenwriter's Compass
Screenwriting advice and articles: "Navigating the art, craft,and business of film writing. From one who's been there and survived to tell the tale."
http://www.screenwriterscompass.com/
Gotham Writer's Workshop
Award winning screenwriting classes online (worldwide) and in New York City.
Also free resources: screenwriting articles and blogs, and more.
ScreenwritingCourses at WritingClasses.com
Screenwriter's Utopia
Assorted screenwriting resources: articles, interviews, screenplay reviews and more.
http://www.screenwritersutopia.com
SydField.com
Official website of screenwriting teacher, Syd Field.
http://www.sydfield.com
SellAScript.com
Writer's resources, up-to-date details of script sales, screenplays, interviews and more.
http://www.sellascript.com
Script Frenzy
An annual global event in which people sign up for free and write a 100 page screenplay in the month of April, with the support and friendship of the other participants.
http://www.scriptfrenzy.org
MoviePoet.com
"MoviePoet.com is dedicated to the art of screenwriting, in particular, the short screenplay. Each month, we run a free online five page screenplay contest. Our goal is threefold: help writers improve their craft, celebrate our best work, and connect writers and their scripts with filmmakers."
www.moviepoet.com
Talentville
Online city for creative people. Join free, upload scripts, get them reviewed, review other scripts and more.
www.talentville.com
McKeeStory.com
Official website of screenwriting teacher, Robert McKee.
http://www.mckeestory.com
Plots Inc
Official website of screenwriting teacher, Linda Cowgill.
She even answers questions sent by email.
www.plotsinc.com/sitenew/home.html
Creative Screenwriting Magazine
A leading screenwriting magazine (also free screenwriting podcasts)
http://www.creativescreenwriting.com/podcasts/main.html
The Visual Writer
Extensive written guides to aspects of screenwriting and more.
Click on the Screen Writing tab on the left to bring up a list of the different areas of screenwriting.
www.visualwriter.com/ScriptDr/Advanced/Begin.htm
TheWriter'sJourney.com
Official website of screenwriting teacher, Christopher Vogler
http://www.thewritersjourney.com
Simply Scripts
Huge collection of screenplays and treatments for film, TV and more.
http://www.simplyscripts.com
Save the Cat!
Official website of screenwriting teacher, Blake Snyder
http://www.blakesnyder.com/
Celtx.com
Free screenwriting and pre-production software for download.
http://celtx.com/
The Writer's Store
For all your screenwriting supplies.
Also a free articles section.

LindaSeger.com
Official website of screenwriting teacher, Linda Seger
www.lindaseger.com
Scripped
Free online screenwriting software, plus affordable creative support services (screenplay coverage, editing, consulting, registration for copyright purposes).
scripped.com
KarlIglesias.com
Official website for screenwriting teacher, Karl Iglesias
http://www.karliglesias.com
Making Of
Lots of screenwriter interviews, movie news, and more
http://www.makingof.com/insiders/department/screenwriter/39
Screenplay Mastery
Official website of screenwriting teacher, Michael Hauge
http://www.screenplaymastery.com
Poetics
The full text of Aristotle's Poetics online.
http://http://classics.mit.edu/Aristotle/poetics.html
Morphology of the Folk Tale
The full text of Vladimir Propp's Morphology of the Folk Tale online.
http://changingminds.org/disciplines/storytelling/plots/propp/propp.htm
36 Dramatic Situations
The full text of Georges Polti's 36 Dramatic Situations online.
http://changingminds.org/disciplines/storytelling/plots/polti_situations/polti_situations.htm
Screenwriters.com
Interviews with screenwriters, screenwriting masterclasses, movie reviews, and more.
www.screenwriters.com
Mr Media
Interviews with screenwriters and others. Scroll down until you find the long list of people interviewed.
mrmedia.com
Charlie Rose Interviews
Interviews with screenwriters, directors, actors and others.
www.charlierose.com/topic/movies_tv_theater
Cinema and Fiction
Cinema and fiction articles, interviews, nonfiction reviews, fiction reviews, dvd reviews, links (with a big blog list), and daily writing prompts.
cinemaandfiction.blogspot.com
Variety
The latest film and TV news and reviews, and more
www.variety.com
TV.com
Extensive coverage of a large range of TV shows, including episode synopses
www.tv.com
David Bordwell
Official website of film professor, David Bordwell
www.davidbordwell.net
Film Genres
A site covering popular film genres
www.filmsite.org/genres.html
The Scrivener's Fancy
All sorts of goodies can be found on this site. Of particular interest for screenwriting are the contributions of comedian/actor/writer/director Tony Martin on film and television
http://thescrivenersfancy.com
The Hollywood Reporter
Film and TV news and reviews, and more
www.hollywoodreporter.com/hr/index.jsp
Storyboards Inc
A site with lots of storyboards by a range of artists.
www.storyboardsinc.com
Scriptwriters Network
Info on formatting, debunking screenwriting myths, links, and networking in the LA area.
www.scriptwritersnetwork.org