US Department of Labor
Bureau of Labor Statistics: How the Government Measures Unemployment
A detailed publication that explains how the government decides who is counted as unemployed and how they measure unemployment.
US Department of Labor
Bureau of Labor Statistics: Local Area Unemployment Statistics
Provides historical unemployment data for state and metropolitan areas of the United States.
CNN
Cnn Money: Unemployment Rate, State by State
Interactive map from CNN showing the current unemployment rate for each state.