Planet Fallout has created a Google map of the Capital Wasteland in Fallout 3. It includes a rather exhaustive account of the game's various quests, important locations, and various other miscellanea (even the locations of NPCs). The site is also accepting user submitted locations, so be sure to drop your favorite spots and Easter eggs (don't expect it to show up too soon though, as the map is currently flooded with submissions). Be warned that it contains many a spoiler, and you may want to avoid it if you haven't finished Fallout 3 yet. Given the nature of the game, we'd say that's a distinct possibility for plenty of gamers out there.