Based on 'mob speculation,' it's believed that the 'fat PS3s' calendar has a bug in it, which is what is causing the problem. Slim PS3s are working fine, as idol indicated above. This is speculated because consoles that are normally not connected to the internet are also reported to not work. So, it is probably not a problem with PSN, though there may be PSN related issues as well since Sony redesigned their PSN website and other features recently. Who knows...
Hopefully Sony fixes this problem ASAP.