Various sites on the Internet are reporting that BlackBerry users are experiencing trouble for the second time in 5 months.

According to The Boy Genius Report, the blackout is occurring across all networks and is likely a problem with RIM's systems, and not the individual carriers. This time, it is more than mobile email that is being impacted, but all access to mobile data for some users as well.

User reports of problems are coming in from T-Mobile, Sprint, Verizon and AT&T users in the U.S. T-Mobile acknowledged that it is seeing problems with BlackBerry services globally, and not just in the U.S.

The problem appears to be related to BIS email services, and not BES email services.

Update: RIM issued this statement in response to a request for information regarding the blackout issue:

"A software issue caused delays in message delivery for some customers using BlackBerry Internet Service in North America today. No email messages were lost. Although the software issue was resolved, the BlackBerry Internet Service system is still experiencing varying delays in some areas as the backlogs of messages are cleared. Phone and SMS service was unaffected and service for BlackBerry Enterprise Server customers was not impacted. RIM is continuing to monitor the situation and apologizes to customers for any inconvenience."

Correct me if I am wrong, but didn't RIM co-CEO Balsillie vow that BlackBerry users would never experience a blackout similar to the one that occurred several months ago? Open mouth, insert foot...