Senator Hillary Clinton (D) made it official this week by finally revealing one of the worst-kept secrets in political history--she’s running for the White House in 2008. The former First Lady is viewed favorably by 50% of American voters and unfavorably by 48%.

From the beginning, the New York Senator has been ahead in all polling for the Democratic primary. However, a week ago, Illinois Senator Barack Obama (D) had pulled to within a point of the frontrunner. Now, Clinton is ahead 31% to 24%. A week ago, it was Clinton 22% Obama 21%.

John Edwards (D) remains in third place, but dropped three points from last week and now earns support from 12% of Likely Democratic Primary voters.

Former Vice President Al Gore—who has not said he’s running--is the top choice for 6%. A new entrant in the race, Senator Joe Biden, is favored by 3%. Three others earn just 2% support. That list includes the party’s 2004 nominee John Kerry, General Wes Clark, and Senator Chris Dodd.

Both Obama and Clinton fare well in most General Election match-ups against Republicans, but both trail GOP frontrunners John McCain and Rudy Giuliani. See a summary of how all the Democratic contenders match-up with various Republican opponents along with constantly updated favorability ratings.

Senator Joe Biden (D) has also announced plans to run for President in 2008, but he lags behind Republican frontrunners Rudy Giuliani (R) and John McCain (R) by double digits.

An update on Republican Primary polling will be released tomorrow. In our last GOP update, Rudy Giuliani and John McCain were the clear frontrunners.