Some users of Apple's iCloud and iMessage services are reporting outages this afternoon. It appears that Apple is having server problems that are preventing users from connecting. The problems also appear to be affecting developer portals for iOS and OS X. Users were unable to log into the developer portals or iCloud's web portal, while iMessage users' messages were not being sent.
It's not clear exactly when the outage began, though MacRumors first noted it about three hours ago. Apple took notice as well and posted to their iCloud System Status page about the outage. They did not give a timeline as to when it would be fixed other than "ASAP."
Apparently, though "ASAP" really means "PDQ," because the system appears to be back up and running for everyone. According to the system status page, everything is online as of about 20 minutes ago.
There's no information on just how many users experienced this problem (I know I didn't). As you can tell, the entry on the status page for the outage only says that "some" users were affected. There is also no word on what caused the outage.