The entire country of Egypt is off the Internet. Every Egyptian provider, carrier, business, school, and personal computer is now cut off from international Internet access. At 00:34 AM local time, Egyptian service providers went dark, one by one. The "withdrawal" initially appeared simultaneous, but later review shows that they occurred over a period of several minutes.
It seems like the carriers each received notification to shut down separately, rather than everyone being cut off at once by some sort of central killswitch. 93% of Egyptian networks are unreachable right now. One site which remains active is the Egyptian stock exchange.
Text message and phone services have also been shut down. This appears to be an action by the government of Egypt to stop protesters from organizing in opposition to the current government. Reporters inside Cairo give word of riots, tear gas, and other signs of a city on the brink of revolution.
There appear to be no current workarounds to the block in place. Until a regime change takes place, or the protests cease, Egypt's 80 million people will stay offline.