The Census Bureau has released a new website giving interactive access to voting data from the 1996-2010 elections, broken down by state and by demographic characteristics such as age, sex, race, and education. It does not provide measures of partisanship or candidate preference.
The data are from the Current Population Survey, which surveys 50,000 households each month on behalf of the Bureau of Labor Statistics. See the Census Bureau website, with a direct link here. Happy browsing!