Online Screenplay Depositories:

100 Scripts – recommended reading by yours truly… reading in true movie style. — coming soon.

IMSDb
Daily Script
Simply Scripts
Drew’s Script-O-Rama

Cool Sites:

Filmmakers.com

Blogs & Miscellany:

John August
Wordplay
Creative Exec
Screenwriting Info
WriterAction

Forums

Done Deal
Two Adverbs

Periodicals & Publications:

Hollywood Reporter
Variety
Script Magazine
Creative Screenwriting

Essentials:

Writers Guild of America, West
WGA, East
Copyright Office