Weaving:

Fingerloop braiding
versions of 'slentre' braiding with loops of string
http://www.cs.vassar.edu/~capriest/fingerloop.html

Guntrams tablet weaving software
downloadable, seems to be freeware
http://users.iafrica.com/e/ec/eckie/tabletweaving/

Phiala's String Page
collection of techniques such as card weaving, sprang, braiding, nalbinding, etc
http://www.duke.edu/~scg3/string.html

The Card Weaver, online software
no download necessary; the only way I could find to start it was to click on one of the samples.
http://www.theloomybin.com/cw/index.html

Turnstyler 2.0 shareware
tablet weaving drawdown program
http://www.hifiber.com/turnstyl.html

Weaver's Hand
Peter Collingwood's page, lots of links, check the many galleries for drop-dead tabletweaving samples!
http://www.weavershand.com/

Norse:

How to Make a Viking Age Lock
based on a Jorvik find
http://www.maikon.net/wendysweb/hob/lock/

Viking Resources for the Re-enactor
Clothing,textiles & more - well researched, great bibliographies
http://www.cs.vassar.edu/~capriest/vikresource.html

The Viking Answer Lady
Well researched articles on Viking culture and life
http://www.vikinganswerlady.org/

York Archaeological Trust
Very interesting site, ranges from the original Roman fortifications, through Angles, Vikings, medieval and post med. See publications-wooohooo!
http://www.yorkarchaeology.co.uk/

General Interest:

Mira's Medieval Pavilion Resources
Very complete collection of useful articles and links for almost any aspect of the SCA
http://www.currentmiddleages.org/tents/index.html

SCA membership form
Get those membership forms here!
http://www.sca.org/members/us-mem-form.pdf

Society for Creative Anachronism
The official SCA homepage
http://www.sca.org/