There are a couple of times this happens to me....usually its from 1) using BB messenger and it bugs and flashes till i get another bb msg.... 2) facebook will do it if i comment on someones status at the same time someone else is commenting.....
__________________ Current Device
Blackberry 8900 Javelin Previous Devices
Blackberry 8300 Curve (2 Faithful Years)
Blackberry 8100 Pearl (My 1st Love)