Paul Callahan's Page of Conway's Life Miscellany
Stephen Silver's Life Lexicon
Jason Summers's Life page
Alan Hensel's Life page
Alan Hensel's Java applet for David Bell's "Just Friends" rule
Andrew Trevorrow's Golly (cross-platform Life editor)
Mark Niemiec's Life Page
Bob Wainwright's LIFEPAGE
Achim Flammenkamp's Most seen natural occuring ash objects in Game of Life
CA and the lambda parameter [archive link]: Exploring the Space of Cellular Automata
David Griffeath's Primordial Soup Kitchen
David Eppstein's Gliders in "Life"-Like Cellular Automata
Stephen Silver's Small spaceship collection (zip file)
David Bell's homepage
Jason Summers's collection of c/2 rakes
Kellie Evans's dissertation "Larger than Life; it's so nonlinear"
James & Andrea Gilbert's Maze of Life puzzles
Safalra's collection of patterns in rule B368/S245
Descriptions of Life file formats
Paul Chapman's Universal computer [archive link]
Squirm (not really a CA)
H. Koenig's Life blog