From the Associated Press:

Barack Obama effectively clinched the Democratic presidential nomination Tuesday, based on an Associated Press tally of convention delegates, becoming the first black candidate ever to lead his party into a fall campaign for the White House.
Campaigning on an insistent call for change, Obama outlasted former first lady Hillary Rodham Clinton in a historic race that sparked record turnout in primary after primary, yet exposed deep racial divisions within the party.

The AP tally was based on public commitments from delegates as well as more than a dozen private commitments. It also included a minimum number of delegates Obama was guaranteed even if he lost the final two primaries in South Dakota and Montana later in the day.

The 46-year-old first-term senator will face Sen. John McCain of Arizona in the fall campaign to become the 44th president.

Now everyone is waiting for Hillary Clinton to admit defeat. My guess is that she will do so in a few hours.