Hey, gotta chime in on this one to mention some of my favorite sites/discussion boards.
For a swords and swordsmanship specific site try Sword FOrum International at swordforum.com. They have discussion boards for western sword arts, Japanese sword arts and Chinese sword arts, not to mention a lot of general discussion on swords as well.
Also, for a western arts specific site try the Historical Armed Combat Assoc. at http://www.thehaca.com.
They have discussion boards for both armed (mostly swordsmanship) and unarmed MA.