Free stuff
GeeThree Slick Plugins Sampler
Barn Door Close, Barn Door Open, Burst, Drip, Heart Close, Heart Open, Radiator, Sweep, Film Noise, Solarize, X-Ray
Virtix sample effects
Dream Border, Extreme B&W, Flame, Glint, Letterbox, Soft Focus
Stupendous Software (several free plugins included in each package)
Utilities
GeeThree (Matte-Tastic, PiP, Slick Vidmix, Slick Caption)
Information and discussion
Yahoo iMovie discussion group
Yahoo iDVD discussion group
dvSpot (equipment reviews and discussion)