Stompalina over at Rawrbitchrawr pointed us in the direction of a map of Ulduar that was meticulously pieced together by a guild mate. The map contains major spoilers, so do not click on the links if you want everything to be a surprise. The map contains a list of all the possible bosses, including those that haven't been announced yet.
The map also reveals a possible progression through the dungeon, which should be indicative of the relative difficulty of the bosses as players head towards the final boss. It's a rather interesting map, if you're willing to see spoilers. The map is spawling and looks massive. Head on over for a peek at the big dungeon of Patch 3.1. Have I said it was filled with spoilers yet? Well, it's filled with spoilers!