Research in Motion says its two year old BlackBerry App World has crossed the one billion app download mark, and that a beta version of the app store upgrade is on the way.

The news comes about a week after Apple released the news that its three year old App Store for iPhones and iPads had passed the 15 billion app download mark. Apple crossed the 1.5 billion app download threshold about a year after the App Store opened, but of course that was pre-iPad. 

Google recently said its Android Market passed the 4.5 billion app download line.

RIM says its BlackBerry App World is now seeing 3 million app downloads a day on average. Those downloads come from both BlackBerry phones, as well as the new PlayBook tablet computer. 

The beta of BlackBerry App World 3.0 will start later this month and screenshots of it have started to leak out across the BlackBerry blogosphere. A minor update, Version 2.1.4.9, has already started to roll out. 

Word of BlackBerry App World hitting the one billion app download milestone is a needed dose of good news for RIM, which has had a rough year that has included sliding earnings, product delays and mixed reviews for its PlayBook tablet.