The date has been set for June 4th. It will be the most important of his presidency so far. Marc Lynch speculates how Obama will handle Egypt's repressive regime and foreign policy:
Obama could take advantage of the location to forcefully speak out in favor of democratization and human rights. He could point out and favorably cite [Condoleeza] Rice's remarks, acknowledge the weak follow-through, and vow to do better by being more pragmatic and cooperative. If he wanted to be really bold, he could reach out to the Muslim Brotherhood as an example of an organization facing a choice between "resistance" and "constructive partnership", and criticize the Egyptian regime's repression of the Brotherhood at a time when it was trying to play the democratic game. He could do the same on the foreign policy front, reframing the moderate/radical divide into something more constructive. If he does some of that with his usual dexterity, then the Cairo location could go from a negative to a net positive -- and set the stage for the real purpose of the address, which I assume will be to fundamentally reframe America's approach to its relations with the Islamic world.