C-Span has the video. Here's the New York Times write-up:
In one of the most forceful statements he has issued from the White House Mr. Obama said that his demands were not negotiable: Colonel Qaddafi had to pull his forces back from major cities in Libya or the United States and its allies would stop him. The president said that he was forced to act because Colonel Qaddafi had turned on his own people and had shown, Mr. Obama said, “no mercy on his own citizens.”
The president said that with the passage on Thursday night of a United Nations Security Council resolution authorizing military action against Colonel Qadaffi to protect Libyan civilians, the United States would not act alone, and in fact that France, Britain and Arab nations would take the lead. That is the clear desire of the Pentagon, which has been strongly resistant to another American war in the Middle East. Mr. Obama said flatly that American ground forces would not enter Libya.
“Muammar Qaddafi has a choice,” he said. “The United States, the United Kingdom, France and Arab states agree that a cease-fire must be implemented immediately. That means all attacks against civilians must stop.”
“Let me be clear, these terms are not negotiable,” Mr. Obama said in the East Room of the White House. “If Colonel Qaddafi does not comply with the resolution, the international community will impose consequences. The resolution will be enforced through miitary action.”