Google's Gmail email service was hit with a major worldwide outage this morning, rendering the Web-based service useless for three hours. Users accessing Gmail via the IMAP protocol on the iPhone or on a desktop email client weren't affected.
Problems began around 9:30am GMT, and concerned users immediately flooded Twitter with reports of the service being innaccessible, claiming they were seeing either blank screens or '502 server error' pages.
Google's dry response was that it was "aware of a problem with Gmail affecting a number of users... We apologise for any inconvenience that this has caused." The cause of the outage has not been revealed.
As of 12:26pm GMT, the service has been restored.
How to access Gmail during future outages
If you have an iPhone, you can setup the built-in email client to use Google's IMAP protocol. This service sometimes still works, and did this morning, and will give you access to your email -- both sending and receiving. Instructions can be found on Google's help site here.
Similarly, if you have any kind of desktop email client such as Microsoft's Outlook or Entourage, configuring these to use Gmail's IMAP service is simple, and will also give you full access to your email. Instructions can be found here.
If you have another Web-based email service such as Hotmail, you can set it up to pull in your Gmail content. In Hotmail, for example, look under 'Options', then 'More Options', and choose 'Add another account to send mail from'. Then follow the steps, using Google's configuration instructions here.