US Census Bureau
Us Census Bureau: Population of the 100 Largest Cities in the u.s.: 1790 1990
Provides an extensive amount of information on the population of urban areas around the U.S. To skip the written summaries just click on the tables for statistical data.
Other
Demographic Brief: u.s. Urbanized Areas 1950 2000
Collection of sites that display statistics for a number of different characteristics for urban areas. Click on site of your choice.
US Census Bureau
United States Census Bureau: Population Projections Tables
Series of projections for different years.