As of approximately 11:00am, the FASmail service appears to be back to normal and has stabilized. The CPU issues that affected the mailbox servers yesterday and this morning appear to be related to the recent issues with iOS 6.1.x devices connected to Exchange. The team has taken steps to ensure that service is not affected by these devices. Note that these devices are still able to connect to the service. Here is an article on the issue for more information:
Although service is back up and operational, the availability service appears to be experiencing issues for some users. This affects MailTips (which tells you when someone is on vacation when composing a message), Out of Office message configuration, Free/Busy Lookup and Outlook setup. The team is working on correcting this issue. Some users may need to re-authenticate to the Outlook Web App (webmail) client.
Some users have also reported intermittent issues with the Blackberry Enterprise service. The team is currently investigating and will continue to monitor the mailbox servers to ensure that services remain stable.