same problem here... others can barely hear me during a voice call but I can hear them perfectly fine. some of the users on crackberry said it can be software related but I've tried 4 different OS and the problem persists
i'll try and find a service and see if they can solve the problem with the mic
also note that if u speak really close to the right-bottom side of the phone (as u look at it) there's a big difference. I pulled off the plastic thingy on the bottom side of the keyboard and cleaned that zone with a vacuum and a light brush but still no difference. so the mic is buried further inside I would assume and I just cleaned the top protective mesh (that's what it looks like)