Image credit: Arbor Networks.
From the Renesys blog, "Egypt leaves the Internet"
At 22:34 UTC (00:34am local time), Renesys observed the virtually simultaneous withdrawal of all routes to Egyptian networks in the Internet's global routing table. Approximately 3,500 individual BGP routes were withdrawn, leaving no valid paths by which the rest of the world could continue to exchange Internet traffic with Egypt's service providers. Virtually all of Egypt's Internet addresses are now unreachable, worldwide.
Renesys has tracked other widespread Internet routing disruptions; the comments on that site are good.
The BGPmon blog is tracking this from the routing perspective, "Internet in Egypt offline".
One ISP that appears to not be down is Noor.net, at least as of Friday midnight EST.
For another network perspective, Netcraft is tracking reachability of Egyptian government sites that had been attacked by Anonymous.
The Guardian has a live blog, Protests in Egypt.
Al Jazeera has comprehensive news coverage, under the headline Anger in Egypt.
The New York Times has new Egypt cables from Wikileaks, Cables show delicate US dealings with Egypt's leaders.
They show in detail how diplomats repeatedly raised concerns with Egyptian officials about jailed dissidents and bloggers, and kept tabs on reports of torture by the police. But they also reveal that relations with Mr. Mubarak warmed up because President Obama played down the public “name and shame” approach of the Bush administration.