RIM's BlackBerry is experiencing its third day of an outage in Europe, the Middle East, Africa and parts of South America — and now it has started affecting users in the U.S. and Canada, too.

A core switch failure in RIM's infrastructure is to blame, but solving the problem seems to be more complex than just firing up a backup version of a database. BlackBerry users affected by the outage are unable to send and receive email or use BBM and other data services.

Speaking at the BlackBerry Innovation Forum in London Wednesday, RIM's UK and Ireland managing director Stephen Bates said, "We thought we had found the problem but had not. We are working around the clock to get to the bottom of the problem."

He also gave a public apology to all BlackBerry customers, but for many users it will be too little, too late.

On Monday, when the outage started, the BlackBerry Twitter account tweeted: "Some users in EMEA are experiencing issues. We're investigating, and we apologise for any inconvenience." A tweet from Tuesday said: "Message delays were caused by a core switch failure in RIM's infrastructure. Now being resolved. Sorry for inconvenience."

The issues, however, have not been resolved. In fact, things are getting worse, as the outage spreads to Canada and elsewhere in the Americas. We've seen reports on Twitter that it's happening in parts of the U.S. and the Caribbean.

While the complaints about BlackBerry are mounting on Twitter and other networks, one of RIM's biggest competitors, Apple, is due to release iOS 5, iCloud and a new version of Mac OS X Lion later Wednesday, and the iPhone 4S hits stores Friday.

Have you been affected by the outage? Share your experiences in the comments.