a friend of mine recently turned me onto a very cool website that allows role players to organize, update, and manage the game on both the player character (pc) and game master (gm) side of the house (or screen as it were)!
obsidian portal allows a gm to build a world and keep track of all the cool bits and bobs online.
you can add maps, build out non-player characters, create and add unique items for the players, as well as continually update the wiki part of the campaign with notes, hints, and information.
additionally, there are secret buttons that provide a gm with a way to share information with one character while keeping all the others in the dark, and a gm with an ipad or other tablet pc could easily have obsidian portal open and running during the adventure to keep gm-only notes, items, and npcs at their very fingertips.
clever players can add their characters, complete with bios, links to adventure sights, and specialty items.
the really interesting thing about obsidian portal, is that it's pretty much only limited by the imagination of the gm and players. if you're a role player at all, get your group to check it out!