Thanks Andy, but I've checked my Main Messages folder and the folders for the 3 other email addresses on my BB, but none of them have any unopened notifications. I thought it may have been from one of the apps I installed, but I've installed nothing new in the past several weeks that would trigger a notifcation.
SwitchBeach - AT&T is my carrier. I have updates available in App World (for all the messenger apps), but none correspond with this icon.
jem9777 & Kellyjdrummer - I agree, it does look like the flashlight icon, but there is no update pending for it in App World.