Blizzard has put a pretty neat little Flash-y WoW Atlas online, featuring clickable and cool-looking maps of almost everything there is to find (officially) in World of Warcraft. It's a pretty solid, if basic interface, so if you're just looking for the closest profession trainer, or want to know where the latest and greatest flight paths are, you're all set.
However, there is of course lots more information online about what there is to find in Azeroth. MapWoW is a pretty invaluable unofficial resource-- it'll show you not only the Alliance and Horde flight paths and towns, but it utilizes the Google Maps API to show where Herb, Ore, and even overworld Treasure Chests show up. It's not quite as groovy as Blizzard's official interface, but there's a lot of extra info too that Blizzard doesn't want to give away.
And the other problem with the WoW Atlas is that while it's up to date for the live realms, there's stuff coming that doesn't yet appear on there. Zul'Aman is seen (just like on the ingame map), but isn't listed as a real instance in the Ghostlands. And unfortunately there's no sign at all of the Sunwell, and not a single mention of Northrend. I clicked around a while and couldn't find any easter eggs, either (unlike Blizzard's other Flash features). Still, it's a neat way to see the official side of Azeroth.
[ via Murdering Murlocs ]