By Ellen Wulfhorst
NEW YORK (Reuters) - Democratic U.S. Senator and former first lady Hillary Rodham Clinton on Saturday entered the 2008 presidential race, officially joining a crowded field for her party's nomination.
"I'm in. And I'm in to win," Clinton wrote on her Web site that reads "Hillary for President."
The second-term U.S. senator from New York and former U.S. first lady had been widely anticipated to announce her bid to become the first woman to win the U.S. presidency. She is considered a front-runner among five other candidates in the Democratic White House field.
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Her announcement comes days after a similar move by Democratic Sen. Barack Obama of Illinois, who is expected to be her leading party competitor and whose campaign could make him the first black U.S. president. Obama's candidacy has stoked enthusiasm among Democrats looking for an alternative to Clinton, who some fear could be too polarizing to defeat a Republican candidate next year.
"I am forming a presidential exploratory committee. I am not just starting a campaign though, I am beginning a conversation with you, with America," she said in a videotaped message on her Web site. An exploratory committee is a first step toward official candidacy and allows her to raise campaign funds and hire staff.
"After six years of George Bush it is time to renew the promise of America," she said.
President George W. Bush was elected to a second four-year term in 2004.
Official Senate portrait of Hillary Clinton.

Releasing a video on her website, Hillary Clinton announced today that she will be forming a presidential .

"I'm in. And I'm in to win", the  Senator for New York announced on her website today, confirming the widely held assumption that she will seek the U.S. presidency in 2008. This is widely speculated to be in immediate response to senator Barack Obama's presidential exploratory committee announcement earlier this week.