Planet Fallout website opened quite useful project - help database, which holds all valuable information regarding Fallout 3. Including full interactive map, open to users. So, if you've found an awesome location you may share it with the community. This database also holds quest information, weapon and monsters, etc.
Lets remind ourselves that there is no reason to rush trying to finish Fallout 3 because game developers left out the ability to come back to virtual world once you complete your quest. Thankfully, if you try to complete every mission it may take long months before you complete the game.