I have been meaning to do this one for a while so I created Category:Webcomics (under Publications). I know there are more out there so please add them directly or leave titles and URL's in the comments here!
I hope the utility of the new category is obvious. The proliferation of webcomics featuring LEGO and the difference between other types of publications seemed a natural division.
Of course when it came to The Brick Testament it was a bit hard to decide if it should move to the new sub-category. The online version shares many attributes of a webcomic, ie: sequential panels, narrative but it is non-fiction in the sense that Brendan does not make up the stories.