For Readers:
Abyss & Apex
Aeon Speculative Fiction
Apex Science Fiction and Horror Digest
ChiZine
Emerald City
Lenox Avenue
LitHaven
Locus Online
MultiVerse
Rogue Worlds
Sam's Dot Publishing
SCIFICTION
SFReader.com
Simulacrum
Strange Horizons
Tangent Online

Writers:
Expressions
Horror Writers Association
Quintamid
Ralan's SpecFic & Humor Webstravaganza
Science Fiction and Fantasy Writers of America
Science Fiction Poetry Association
Speculations

Of Artistic Interest:
Interstitial Arts Foundation
Speculative Literature Foundation