For other SF related information, you may want to look at:

• Timebinders - a fan history group
• FANAC fan history archives
• Internet Speculative Fiction DataBase
• The Science Fiction and Fantasy Research Database
• SFsite - home of several SF organizations (This is no longer updated.)
• The SFWA homepage
• The ASFA homepage
• The Gunn Center for the Study of Science Fiction
• Money-Saving Guide for Authors and Writers

Worldcons and NASFiCs

(Many previous worldcons are no longer available at their original URLs.)

• The Worldcon homepage
• Wikipedia list of NASFiCs
• Conucopia (the NASFiC in 1999)  (Internet Archive. Originally www.99.nasfic.org.)
• Aussiecon 3 (the Worldcon in 1999)
• Chicon 2000 (the Worldcon in 2000)
• The Millenium Philcon (the Worldcon in 2001)  (Internet Archive. Originally 2001.worldcon.org.)
• ConJosé (the Worldcon in 2002)
• Torcon 3 (the Worldcon in 2003)  (Internet Archive. Originally www.torcon3.on.ca.)
• Noreascon Four (the Worldcon in 2004)
• Interaction (the Worldcon in 2005)  (Internet Archive. Originally www.interaction.worldcon.org.uk.)
• Cascadia Con (the NASFiC in 2005)  (Internet Archive. Originally www.cascadiacon.org.)
• L.A.con IV (the Worldcon in 2006)  (Internet Archive. Originally www.laconiv.org.)
• Nippon 2007 (the Worldcon in 2007)
• Archon 31 (the NASFiC in 2007)  (Internet Archive. Original lywww.archonstl.org/31.)
• Denvention 3 (the Worldcon in 2008)
• Anticipation (the Worldcon in 2009)  (Internet Archive. Originally www.anticipationsf.ca.)
• Aussiecon Four (the Worldcon in 2010)
• ReConStruction (the NASFiC in 2010)  (Internet Archive. Originally www.reconstructionsf.org.)
• Renovation (the Worldcon in 2011)  (Internet Archive. Originally www.renovationsf.org.)
• Chicon 7 (the Worldcon in 2012)
• LoneStarCon 3 (the Worldcon in 2013)
• LonCon 3 (the Worldcon in 2014)  (Internet Archive. Originally www.loncon3.org.)
• Detcon1 (the NASFiC in 2014)
• Sasquan (the Worldcon in 2015)
• MidAmeriCon II (the Worldcon in 2016)
• NorthAmeriCon '17 (the NASFiC in 2017)
• Worldcon 75 (the Worldcon in 2017)
• Worldcon 76 San Jose 2018
• Dublin2019
• ConZealand Worldcon in 2020
• DisCon III, the 2021 Worldcon

Science Fiction Clubs

• Arisia, Inc.
• Baltimore Science Fiction Society (BSFS)
• The Bay Area Science Fiction Association (BASFA)
• Cincinnati Fantasy Group (CFG)
• Denver Science Fiction & Fantasy Book Club
• Fandom Association of Central Texas (FACT)
• Latham-Albany-Schenectady-Troy Science Fiction Association, Inc. (LASTSFA)
• Los Angeles Science Fantasy Society (LASFS)
• Massachusetts Convention Fandom, Inc. (MCFI)
• MASSFILC, The Filk Music Club of New England
• MIT Science Fiction Society (MITSFS)
• Minnesota Science Fiction Society, Inc (Minn-StF)
• The National Fantasy Fan Federation (N3F)
• The Orlando Area Science Fiction Society (OASFiS)
• Oregon Science Fiction Conventions, Inc. (OSFCI)
• Philadelphia Science Fiction Society (PSFS)
• Rhode Island Science Fiction Club (RISFC)
• South Florida Science Fiction Society (SFSFS)
• Southern Fandom Confederation (SFC)
• Washington Science Fiction Association (WSFA)
• Worcester Polytechnic Institute Science Fiction Society (WPISFS)

Also see this list of organizations.

Science Fiction Publishers

• Analog Magazine
• Harper Collins SF (which absorbed Avon, among others)
• Baen Books
• Donald M. Grant Books
• Penguin (which absorbed Putnam, Berkley, DAW, and Ace)
• The Science Fiction Book Club
• Random House (which absorbed Ballantine, Bantam, del Rey, and LucasBooks)
• Tachyon Publications (another small press)
• Tor Books
• Angry Robot Books
• Orbit Books
• Pink Narcissus Press
• Suberranean Press

SF Community on the Net

• NESFA members on the Web
• Home pages for authors on recommended list