Anyone who's interested in the general history of tafl games, of which tablut is one, might like to have a look at my site about the game, which is completely rewritten and uploaded this morning:
The highlight of the site is an applet for Java-equipped web browsers, which allows you to play the game against a friend using whatever board layout and rules you select (i.e. a virtual board). I've also put a drawing on there, something in the likeness of an authentic tablut game, as Linnaeus would have witnessed it (based on his own drawings).