MapWoW is one of my favorite WoW resources online. I have to admit, I don't use it as much as some other helpers, but it's really well done -- someone put the Azeroth map inside the Google Maps interface, and added herbs, ores, flight paths and everything else you need to find on the map. If you've ever asked "where can I find..." in a chat channel, odds are that MapWoW had the answer already.
And now they've got Northrend in the mix, ready to go for your exploring needs. It's a little spoilery, actually -- a pretty detailed bird's-eye view of all the new content in the expansion. They do have flight paths included, but they don't quite have herbs and ores uploaded yet -- we're told they'll be in soon.
Don't get me wrong -- there's definitely something to be said for exploring: pretty soon, we'll have tagged and catalogued every single mob up there, so it is fun to just run around now while it's all still a new world. Don't depend on maps right away, because you never know what might be just around the corner in the land of the Lich King. But if you need it, there's your map.