CNN rushed to report that Clinton will acknowledge tonight that Obama has secured the delegates necessary to win the Democratic presidential nomination, based apparently on this AP report which suggests that she will concede tonight. Clinton adviser Terri McAullife then rushed out to correct that misimpression, stating Clinton has no intention of conceding in her planned speech tonight following the close of the last Democratic primaries. Now, contradicting the CNN story I linked to above, the AP reports based on their own calculations that Obama has obtained enough pledged delegates to secure the nomination. There's no word as to whether Clinton will acknowledge such (unlikely) or concede (even less likely) but I'm sure other media organizations are rushing to confirm the AP's results. We'll see what they say, maybe as early as this afternoon or tonight.
UPDATE: The AP has updated their report. Their figures are based on a tally of public and private commitments by super-delegates, as well as the pledged delegate total (at least as I can best make out.) The report still indicates that Clinton will acknowledge Obama's lead, but not that the she will either terminate or suspend her own campaign.
UPDATE II: A colleague of mine who's in a position to know indicates that Clinton is preparing to concede to Obama (though not tonight.) She seems to have little choice, as Obama appears poised to secure the necessary delegates and her last hope would be a challenge to the delegation allocation at the Democratic convention. It's more likely that lightning will strike Obama than that she will secure the nomination in this manner. This updated AP report would seem to confirm the news of a soon-to-be concession as well; according to the report, Clinton is now prepared to discuss the possibility of taking the VP slot alongside Obama. Truly, nothing would make me happier.