Some Experiencing Delays and Failures When Sending iMessages [Update: Fixed]

According to reports on the MacRumors Forums and on Twitter, Apple's iMessage SMS-replacement service is currently experiencing some sort of system outage.

Users are experiencing difficulties with delayed messages, messages completely failing to send, as well as read receipt notification errors. The problem is intermittent and not universal, but given the high-profile that Apple places on the service -- it's enabled by default on every iOS device -- any sort of outage is going to affect many users.

We've emailed Apple for comment and a timeline for a resolution, but have yet to hear back.

Update: iMessage appears to be working again for many.