I had this same issue for a while. Google search for a program called "not call log prefs". This app is not in the android market. This app will basically allow you to set your phone to go to the home screen rather than the call log window where you can accidentally dial someone. When you end a call either via bluetooth headset, or on screen button, you will be redirected to your home screen. I have not pocket dialed anyone for the last 6 months thanks to this.
Good luck. Hope this helps