We also have a rather large play-by-post game going on over at
http://brennor.dyndns.org/rpg/Forums/viewforum/f=536.html. I'm unsure if the GM has any open slots, but you can send him a PM. We just added a bunch of players over the last month, but some of them are starting to disappear, so there could be an opening. We're a pretty consistent group of gamers. Most of us have been on the site playing for 5-10 years together. We also have tons of other systems (d20, Pathfinder, L5R, Star Wars, home brews, etc.).