I think most people looking for MP games here tend to look in the sub-forums section devoted to it:
http://forum.shrapnelgames.com/forumdisplay.php?f=145
If you look in there you'll also find a lot of examples of posts & the kinds of details people usually include for their game settings and whatnot. The more details you can give people about your game, the better a sense potential players will have of if they want to join your game. Also makes you seem all organized and on top of things if you can tell people what your game settings are.
Valerius' "Myth" a good example of succinct settings post:
http://forum.shrapnelgames.com/showthread.php?t=47744
iRFNA's "SeaOfInnocence" a good example of long form game thread post:
http://forum.shrapnelgames.com/showthread.php?t=47172
Wraithlords' "DHG - Deadhouse Gates" another good example of above, w/ theme / backstory stuff:
http://forum.shrapnelgames.com/showthread.php?t=47401