Movies
The Star Wars Trilogy, besides being an all-around fantastic set of movies that everyone should watch, is also an extremely accurate depiction of what it means to live in a toltalitarian society. For those of you who don't already know, these movies were directed by George Lucas in the late seventies and early eighties. New, re-created versions of these films were released in early '97 and are now available on video in addition to the older versions.
Another one of George Lucas's movies that accurately portrays a totalitarian society is THX 1138. This movie, the first that Lucas directed, is powerful and moving despite its lack of great comercial success. This movie is a must-see if you need to see a technocratic totalitarian society in action or if you're just looking for an awesome movie.
Swing Kids, released in the early nineties, is a movie about the swing-related resistance to the Nazi regime. It's moving and powerful and all that jazz, and also pretty fantastic if you're into music and dancing.
The Wave is a great movie about crowd control, propoganda and how Hitler got into power.
Books
George Orwell is the author of two great books about totalitarian societies: Animal Farm and 1984. Animal Farm is about a group of animals who take over a farm in the name of freedom and democracy. Eventually, however, the pigs gain control over the rest of the animals and it becomes a totalitarian state. This is a great book just for reading, and also is a good parable of what happened in the former USSR. 1984 is about a totalitarian society which controls and changes its recorded history to ontrol the populace.
Brave New World, by Adolus Huxley, although it's not strictly about a totalitarian society, is still a good look at what happens when humans try to control the human world.
Sybil Claiborne's In The Garden of Dead Cars shows the control-freak, nymphophobic society that takes over the world after an STD epidemic destroys most of the world's population. It's not quite as popular as some of the books listed on this page, but it's a great read.
Ayn Rand's Anthem is an all around fantastic book in addition to being about a totalitarian society. The novella chronicles the life and times of a man in a society where are are forced to be equal and are kept from being individuals.
Another book that Simon (don't you feel special now, Simon?) insists I include here is Ray Bradbury's Farenheit 451, which is about a totalitarian society where creativity and fiction are declared outlawed. The lack of books is, for me at least, more frightening than anything Stephen King could ever think of.
Last but never least come the books by the science fiction grandmaster Robert A. Heinlien. His three books about totalitarian societies that stand out are Revolt in 2100, in which a fundamentalist church takes over the country; Beyond This Horizon, about a movement to take ove the world and create the superman through eugenics and genetic; and The Day After Tommorow, about an invasion force which conquers the United States and holds it prisoner.