2011/04/20 - Unscheduled Internet Outage
At about 3.45AM, all South African higher educational institutions lost access to the international Internet.

You will likely experience this outage as an ERR_DNS_FAIL or ERR_CONNECT_FAIL error when trying to access websites hosted outside South Africa (even those ending in .za). When accessing secure (https://) web sites, your browser may report that the connection has timed out or the site is unreachable.

The reason for the outage would appear to be a fault on the SEACOM submarine fibre optic cable. No further information is known at this time.
I've had confirmation that this is a SEACOM problem, which may or may not be related to the scheduled work they did yesterday. Estimated time to restore is 12.30PM this afternoon.
We've received the following feedback from TENET:

I've just spoken to the SEACOM NOC and they claim the Estimated Time to Repair (ETR) is 5 hours from now at approximately 12:30pm. There was no Reason for Outage (RFO) specified.

I will continue to feedback as/when I have more information.