UPDATE: Marc Lynch wonders if Mubarak was planning to resign but changed his mind, and has this to say:
"It's hard to exaggerate how bad Hosni Mubarak's speech today was for Egypt. In the extended runup to his remarks, every sign indicated that he planned to announce his resignation: the military's announcement that it had taken control, the shift in state television coverage, a steady stream of leaks about the speech. With the whole world watching, Mubarak instead offered a meandering, confused speech promising vague Constitutional changes and defiance of foreign pressure. He offered a vaguely worded delegation of power to Vice President Omar Suleiman, long after everyone in Egypt had stopped listening. It is virtually impossible to conceive of a more poorly conceived or executed speech.
"Omar Suleiman's televised address which followed made things even worse, if that's possible, telling the people to go home and blaming al-Jazeera for the problems. It solidified the already deep distrust of his role among most of the opposition and of the protestors, and tied his fate to that of Mubarak. Even potentially positive ideas in their speeches, such as Constitutional amendments, were completely drowned out by their contemptuous treatment of popular demands. Things could get ugly tonight --- and if things don't explode now, then the crowds tomorrow will be absolutely massive. Whatever happens, for better or for worse, the prospects of an orderly, negotiated transition led by Omar Suleiman have just plummeted sharply."
UPDATE: Egypt's U.S. ambassador claims that Mubarak transferred all power to Suleiman.