Unless higher-level officers in the Egyptian army turn against the government, this protest wave will not turn into a revolution. Mubarak has shown that he's willing to go far - as far as the Iranian regime did - in crushing the protests. There cannot be regime change without the army losing faith in Mubarak or the president himself stepping down. And I don't know that the army has a party or a leader it would back beside Mubarak.
These protests were only possible because of the relative liberalization of Egypt and the comparatively free access of so many educated young people to new media and communications (until Mubarak shut the internet down!). By way of contrast, see how quiet Syria is in comparison; this kind of popular and sophisticated grassroots organization simply would not have been possible there.
Nevertheless, this is a new political dynamic in the Arab world. Tunisia and Egypt are seeing true popular upheavals. And because these states never achieved the kind of modern, mass mobilization of their populations built up by the Iranian regime since the Islamic revolution and the Iran-Iraq war, Tunisia and Egypt depend (in Tunisia, depended) on their military and security apparatuses in the face of opposition. In Iran, you had ideologically-motivated popular militias and activists fighting on behalf of the Iranian state against the opposition protesters. In Egypt, you only have paid soldiers, loyal to the institution of the army and, for now, to the president.But as long as they remain loyal, the regime will not fall - at least not in the short-term. Tunisia's police and army were ultimately too weak and too unwilling to fight for the dictator there. But Egypt's army is much larger and Mubarak's support there seems deep enough for it to continue to side with him.
Another comparison: The violence in Lebanon following the fall of the government represents a much more familiar phenomenon. Basically thuggery along sectarian lines.