East Street games offers Valhalla, a set of free wargames rules for Dark Age skirmishes. The rules are free for the downloading, or for purchase in print. The website has an online system for generating warbands. Interesting stuff.
Saxons and Vikings is a set of four page simple rules for Dark Ages battles
The Command Tent has a nice post on how to scratch build a viking A frame house. I’m going to build a couple of these for my Viking/Saxon/Norman games.
The Man Cave has a couple of printable Viking flags.
Viking Raid is a set of free wargames rules for carrying out a competitive Viking raid. The set uses playing cards as an integral mechanism.