The quick version:
Mubarak stepped down as President of Egypt today, almost certainly from coercion from the Army.
The longer version:
Due to massive pressure Egyptian protesters, everyone (Egyptian Army, CIA, protesters) thought Mubarak would step down on the 10th of February. He made it clear he had no intentions of doing so.
It's unclear why he did this, but it looks like there may have been an internal struggle within the military leadership. The military's Supreme Council released a second Communique on the 11th supporting the idea of Mubarak sticking around, with the Vice President taking some undefined large share of the power (after a first Communique which implied that the army wished for Mubarak to step down). This second Communique suggests that the pro-Mubarak faction of the army had enough influence to stave off the coup and keep Mubarak in power.
This faction likely hoped that the army's support (and a "gradual transition") would depress protesters and mark the beginning of the end of the demonstrations.
It wasn't to be so.
On Feb. 11, the ranks of protesters swelled immensely. Protesters in Suez took over government buildings, and thousands in Cairo began marching towards the Presidential Palace.
The Army was directed to protect the Palace, and surrounded it with troops and tanks. The issue was thus pushed to a critical climax, giving the army 3 options:
1) Risk a violent confrontation with the protesters.
2) Stand by idly and let the protesters overthrow the President, risking the collapse of the entire regime.
3) End the stand-off before it starts by couping Mubarak themselves.
The massive risk of option 1 likely caused a sufficient subset of the pro-Mubarak faction of the army to defect to the anti-Mubarak faction that a consensus to coup was likely reached in the afternoon of the 11th.
The third option was the safest for the army; it allowed the army to fall on the side of the vast majority of the population's wishes. It means that, while there will be a major change in government, Egypt's trust in its army will only swell, making sure that the army will be able to maintain its influence and power in the regime, no matter what happens next.
We'll keep you updated.