The Census Bureau just released the results from the 2010 Census Demographic Analysis project. These numbers are five plausible ESTIMATES of the national population that will be used to help evaluate the quality of the 2010 Census. They are NOT the actual 2010 Census enumerations, which will be released later this month.
The numbers being reported are: 2010 Demographic Analysis Resident Population Estimates for April 1, 2010 (in thousands)
Middle Low 307,415
High Middle 310,038
You can find more details, including estimates for various age, race, Hispanic Origin, and sex groups HERE.