I just added a new link to the Sci-Fi 101 reference list in the right-hand column. A topic no red-blooded Sci-Fi/Fantasy author should miss...government! A great story demands a well-defined government to really muck things up for the protagonist, doesn't it?
Here you'll find an extensive list from Wikipedia of different types of government and links to more details on each. Ever heard of a Grand Duchy? A Grand Prince? What are the various types of Theocracies?
Go have a look here: