Guidebooks and useful information by Dabs
It's important to get a recent guidebook as things seem to be changing rather rapidly in Romania. I would recommend getting the Rough Guide and/or Lonely Planet, they seem to handle Central & Eastern European countries with more depth than Fodor's or Frommer's.The best online resource I found was In Your Pocket and you can also pick up an updated copy once you get to Bucharest. This information seemed to be the most reliable as it is updated more frequently than the guidebooks.
I read a couple of interesting books before I left on the trip, one on the Ceausescu's and one on Vlad Tepes and his ties to vampire lore.