I'm currently playing in a PENDRAGON 1e PbP game, located here: http://makofan.proboards.com/index.cgi (the DM is Makofan).
There is currently a spot available for a new knight. You do not have to be familiar with the Pendragon rules to be able to play.
I highly, highly, highly recommend this game. Makofan is an awesome DM and runs a fantastic game. On top of that, Pendragon is a great system, although it has a very different feel than D&D.