I haven't done any work with BlackBerry devices other than some forensics to recover data from dead and fried BlackBerry devices.
But there are people that just spend their day finding out new ways to break things in order to make the world a safer place.
As for getting notifications about this, there are tons of people that put this information out, and most people that work in this space aggregate all of it and have to read everything, every single day!
If you wanted to know about security problems with BlackBerry devices and didn't want to deal with everything else, you could probably setup a Google Alert for BlackBerry RIM Vulnerability.
I'm wondering if I am even answering the question the right way.