Time to use that!
I've had a Blackberry Curve for seven months now and the trackball has begun to stick.
When I remove the battery for a few seconds and then return it the problem seems to be fixed - for a short while. Then it happens again.
I've read somewhere that it is a simple question of removing the trackball and cleaning it out, but this is easier said than done. I have tried it from all angles with all manner of implements, failed, and have now probably invalidated my warranty.
My provider told me to install some new software but that doesn't seem to have helped.
Does anybody have any ideas?