Organizations that publish and that you should join.
The Japanese Sword Society of the US. http://www.jssus.org
Click on JSL Index on the top bar and you'll be taken to the Index of Japanese Sword Literature, which indexes many of the books I sell.
NBTHK American Branch. http://nbthk-ab.org/cleaning-maintenance.html
This link takes you to their Sword Care and Etiquette brochure, which everyone should read.
The Northern California Japanese Sword Club. http://www.ncjsc.org/
The Nihonto Message Board. http://www.nihontomessageboard.com/
The NMB is likely the premier gathering spot online for us Japanese sword nuts.
Other sword book dealers in the West.
Paragon Books in Chicago. http://www.paragonbook.com
Alan Bale in the UK. http://www.japaneseswordbooks.com/
Other sword dealers I can recommend.
Andy Quirt. http://www.nihonto.us/
Robert Benson. http://www.bushidojapaneseswords.com/
Fred Guyer. http://www.swordsandtsuba.com/
Fred Weisberg. http://www.nihonto.com/
Darcy Brockbank. http://www.nihonto.ca/index.html
Danny Massey. http://www.nihontocraft.com/japanese_sword_home.html
Byron Shimizu. http://www.samuraiswords-hawaii.com/index.html
David Bond. (swords, fittings, pottery, prints, etc.) http://www.blackship.gallery
David Stiles sells Japanese art, including swords and fittings. https://www.tsubaotaku.com/
Mike Quigley (Japanese swords, Oriental art/antiques, WWII militaria), http://shogunorientalarts.com
The Big Kahuna
Richard Stein's Japanese Sword Guide. http://www.japaneseswordindex.com/nihonto.htm
Jim Gilbert has a very informative site about tsuba. http://home.earthlink.net/~jggilbert/tsuba.htm