But the fandom can always use a little nudge to get people together. So I found this forum:
The House of Lore
They've got a whole section on Prydain, that seemed to have initially had a good bit of activity, and has since lost steam. I encourage any fans, particularly those who like to discuss the books from a literary/intellectual point of view, to visit and see if we can drum up some more interest within the board. Although many of the posters seem to be tween-age kids, there are a few that seem like they could actually have an intelligent conversation if anyone was around to encourage it. (Not to run-down tweenage kids, whose enthusiasm I appreciate but whose propensity for ignoring basic English grammar sort of sticks in my craw). Anyhoo. Check it out.