GMMichael
Guide of Modos
Don't worry, use them as a resource. It is okay to give up some narrative control, and be informed by the players.
+1. Players who know too much are your friends, not your enemies. You can ask them to inform you when you get to a rough patch, or you can ask them to actually narrate part of the story/setting. If a PC can't handle player knowledge properly, you throw in a twist to keep him on his toes. (If a player can't handle twists, he's probably playing the wrong type of game.)
The GM's job isn't to know everything - it's just to make things fun.