My Blackberry has a LED flash for the camera and there's a Flashlight app available for like a dollar. I found it to work much better than a traditional flashlight.
The problem with that is that its gonna drain your battery and eventually screw up your battery life...the original BB battery comes for around $70 + tax vs a flash that you can buy at bronte for $6 + tax...trust me on the battery thing, i know it from experience.