Hey gang, Just thought I would share, I had a problem with my 9700 when making a call it would switch from headset and handset mode. Called Rogers and they could not figure out what was wrong... Since my device is under the 30 day mark they are shipping me a new replacement. My friend had the same problem with 8800 blackberry and it fixed with an easy trick. It seems that some times if you plug a headset into the jack the contacts get stuck. so he just plugged in another headset and it fixed the problem.
Just putting this out incase it can help someone else.