Liquidor posts on the forums about a cool little tool he's put together. His rep calculator is a one-stop shop for everything you need to know about where your character is at in terms of rep, and what you need to rep up. There's just one little catch-- since Liquidor plays on Boulderfist EU, the calculator only works for EU characters at the moment.
So those of us on US realms are out of luck, but maybe if we give Liquidor a little more attention here, he'll be convinced enough to let us Americans in on the fun. As much as rep grinding is required in the game now, it's interesting that there's not a lot in terms of reputation tools out there-- WoW Wiki has those cool charts for each rep and the quests that can be done to level it, but Liquidor's guide is unmatched in terms of utility-- he even tells you mobs that can be killed for rep, and how many are needed of each type to rep up. Hopefully, especially as we move toward the next expansion (where even more factions will likely be introduced), players will get better and better tools like this to help their rep grinding.