Useful Links

Tutorials:
Video CoPilot
An excellent source for After Effects tutorials, coherent and well constructed. This site proved a God-send during the editing of Stallion Head 3
Indy Mogul
Another excellent source for special effects and stunt tutorials for cheap, fun filmmaking
Tom Antos - Film Guru
A guy who does really good youtube videos about filmmaking, including explanations of basic filmmaking principals such as depth of field.
Smashing Magazine - Photoshop Tips and Tricks
Whilst this is a photoshop tutorial site and not a filmmaking site, a lot of the principals in editing techniques can be applied to film, which is extensively explored here.
DIY Film Gear
who said you need to be rich to have film equipment?

Tools:
Kuler
an excellent tool for assigning colour schemes to films
Screen Writing U
includes an excellent page on the "ten commandments" of screenwriting

Creative Commons Music:
Free Music Archive
Beat Pick
Magna Tune
Jamendo
CC Mixter

General Filmmaking Stuff:
filmmakers.com
Film School Rejects
filmmaking.net
Film Underground
Kermode and Mayo Film Reviews, Radio 5Live
Roger Ebert - Chicago Sun Times/