I just poked around on Plothook and Burning Void, and I gotta agree that they don't look all that useful. I did find
http://www.plothook.net/RPG/forumdisplay.php?f=40 for a "meet players" deal, but it doesn't look too extensive.
Try Googling for "gamer classifieds" or some such? It'd probably be easier to hit a specific game's site to look for people.
Or just be one of those guys who hangs out at a gaming store for 5 hours a day. I'm sure you'll meet all sorts of freaks. I mean
folks. Folks.