THIS APP ONLY WORKS ON THE 8100 PEARL WITH OS 4.2. IT WILL NOT WORK ON ANY OTHER BB MODEL INCLUDING THE 8110, 8120, or 8130 (they don't contain the colored LED's the are in the 8100) If your 8100 device is running OS 4.5 use the new BlingBall app here.
I know there's already a program to change the trackball color, but it had no OTA install, so I never got around to installing it, and also wanted something I had more control over.
It's pretty simple right now, all it has is enable/disable and color selection. You can set these in Options->ColorPearl.
You can download it here
I plan to have more options at some point, but need suggestions on what they should be.
Edit: Version 0.2 is out, same download location!
Colors: White, Red, Green, Blue, Cyan, Yellow, Pink, Custom (Hex RRGGBB), Random!