Articles/Bloggers/Advice:
Writing for Stage/Screen - writingforstagescreen.suite101.com
Scriptwriting Secrets (free e-book) - www.scriptwritingsecrets.com/
Robert McKee's Official Website - www.mckeestory.com
Syd Field's Official Website - www.sydfield.com
John Truby's Official Website - www.truby.com
Linda Segar's Official Website - www.lindaseger.com

Screenplay Copyrighting:
Official Government form for copyrighting with Library of Congress - www.copyright.gov/forms/formpai.pdf
Registering Script with Writers Guild of America (W.G.A.) West - www.wgawregistry.org/webrss
Registering Script with Writers Guild of America (W.G.A.) East - www.wgaeast.org/

Selling your scripts:
Resources for selling your script online - www.inktip.com

Software:
Final Draft - www.finaldraft.com
Movie Magic - www.screenplay.com
Sophocles - www.sophocles.net

Supplies:
Writers Store Online (Best supplies resource) - www.writersstore.com
Recording your script/hearing it read - www.iscript.com

Online Screenwriting Forums:
BBC Writers Room- www.bbc.co.uk/writersroom
Trigger Street- www.triggerstreet.com
Wordplayer - www.wordplayer.com
Script Nurse - scriptnurse.com/wcms/index.php
Writers Write - www.writerswrite.com

Hard-To-Find Screenplays:
Hollywood Book & Poster: Online: www.hollywoodbookandposter.com
Phone: 323-465-8764
E-Mail:scripts@hollywoodbookandposter.com