The BlackBerry-maker Research In Motion (RIM) today has finally fixed a flaw that left North American users without BlackBerry Messenger, sporadic email delivery, and no web browsing yesterday and late into the morning today.

This interruption of service marks the second BlackBerry service outage in less than a week, the last one occurring on December 17.

The BlackBerry Curve was the top selling smartphone in the United States in the first quarter of 2009, giving RIM a 50-percent share of the total smartphone market in the U.S.

RIM most recently posted strong Q3 2009 earnings and added 4.4 million new subscribers in the quarter, bringing the total BlackBerry user-base worldwide to 36 million.

RIM blamed a flaw in an updated version of the BlackBerry Messenger app for causing the outage. The company is encouraging users to upgrade to the latest version 5.0.0.57 of BlackBerry Messenger. Just remember to upgrade first.

RIM spokeswoman Rachel Colley confirmed today in an email that the problem has been fixed.

A service interruption occurred Tuesday that affected BlackBerry customers in the Americas. Message delivery was delayed or intermittent during the service interruption. Phone service and SMS services on BlackBerry smartphones were unaffected. Root cause is currently under review, but based on preliminary analysis, it currently appears that the issue stemmed from a flaw in two recently released versions of BlackBerry Messenger (versions 5.0.0.55 and 5.0.0.56) that caused an unanticipated database issue within the BlackBerry infrastructure. RIM has taken corrective action to restore service.