Medieval Re-creation
The Association for Renaissance Martial Arts <http://www.thearma.org/>: includes resources such as historical manuals and pictures about medieval fighting.
The Society for Creative Anachronism <http://www.sca.org/>.
Castles
Castles Abbeys and Medieval buildings photographed my Michael Cook: http://www.castles-abbeys.co.uk/?CFID=4137851&CFTOKEN=63710384.
Castles of Britain <http://www.castles-of-britain.com/index.htm>: a site "dedicated to the study and promotion of British castles" with links to numerous essays, trivia, photos.
A guide in pictures to medieval castles in England, Wales and Ireland <http://www.pictures-of-castles.co.uk/> Picture of about two dozen castles, even at various times of the year.
Castles of Tuscany <http://www.castellitoscani.com/castles_index.htm>: alphabetical list with links to pages of description and pictures of 177 castles and 15 other sites.
Castles on the Web <http://www.castlesontheweb.com/index.html> dozens of links with brief description of content to various castles and medieval life.
Castles of the World <http://www.castles.org/index.htm>. Links to castles with comments from visitors.
Italian castles (in Italian) http://www.mondimedievali.net/castelli/index.htm
Guide to Castles of Europe <http://www.guide-to-castles-of-europe.com/index.html>. Organized by country, with info on many castles.
Bayeaux Tapestry
http://headlesschicken.ca/eng204/texts/BayeuxTapestry/
http://www.angelfire.com/mb2/battle_hastings_1066/bayeux_tapestry/index.html
Froissart
The Online Froissart:
https://www.dhi.ac.uk/onlinefroissart/
Tales from Froissart: http://faculty.nipissingu.ca/muhlberger/FROISSART/TALES.HTM
Some illuminations of Froissart: http://en.wikipedia.org/wiki/Froissart_of_Louis_of_Gruuthuse_(BnF_Fr_2643-6)
some illustrations of tents from Froissart : http://home.adelphi.edu/~sbloch/sca/tents/pictures/froissart/
Master of Getty Froissart: http://www.getty.edu/art/gettyguide/artMakerDetails?maker=21261
Chivalric Images
Medieval French Illuminations of War, Enluminaires <http://www.enluminures.culture.fr/documentation/enlumine/fr/visites_00.htm>: click on "La guerre" for warfare; other links have interesting pictures of medieval life and people.
Manesse Manuscript <http://diglit.ub.uni-heidelberg.de/diglit/cpg848> Gorgous illuminations of Minnsaenger/German Minstrel knights of the 12th and 13th Century.
Konstance-weingarner liederhandschrift: <http://digital.wlb-stuttgart.de/purl/bsz319421317>
<http://libwww.library.phila.gov/medievalman/tour.cfm> Some illustrated manuscripts of medieval life.
Digital Scriptorium <http://www.scriptorium.columbia.edu/> collects images of medieval manuscripts from a number of American libraries.
Heraldry
Printed Sources
De Re Militari's primary sources : <http://deremilitari.org/primary-sources/>
Internet Medieval History Sourcebook: on the crusades <http://www.fordham.edu/Halsall/sbook1k.asp>
The Camelot Project <http://d.lib.rochester.edu/camelot-project>
Froissart, Chronicles <http://hdl.handle.net/2027/njp.32101013592199>.
Geoffrey of Monmouth, History of the Kings of Britain <http://www.yorku.ca/inpar/geoffrey_thompson.pdf>.
Jack Cade, Proclamation of Grievances <http://www.fordham.edu/halsall/source/1450jackcade.asp>. Primary Source.
Eurodocs <http://eudocs.lib.byu.edu/index.php/Main_Page>
Websites, short essays, and blogs
Castles on the Web <http://www.castlesontheweb.com/index.htmll>
Women and the Crusades <http://www.womeninworldhistory.com/heroine3.html>
A Commonplace book <http://willscommonplacebook.blogspot.com/> regular entries on medieval warfare
Knighthood orders <http://www.heraldica.org/topics/orders/>
http://www.medievalwarfare.info/
Dress, Jewels, Arms and Coat of Arms: Material Culture and Self-Representation in the Late Middle Ages <http://web.ceu.hu/medstud/manual/SRM/>
Chivalry toolbox: <http://www.cod.edu/people/faculty/staeck/Chivalry%20Toolbox.htm>
course on medieval warfare check links: http://medieval.ucdavis.edu/130/
medieval news: <http://medievalnews.blogspot.com/>
medieval itineraries <http://pilgrim.peterrobins.co.uk/itineraries/>
Medieval English Towns <http://www.trytel.com/~tristan/towns/towns.html#menu>. Diverse information on some specific towns and urban life in general.
Wars of the Roses <http://www.warsoftheroses.com/index.htm>.
Warwick Castle <http://www.warwick-castle.com/explore-castle/map-and-overview.aspx>. Tourist destination.