There's a free program called MortSaver that's supposed to disable all buttons and the display until you press the button assigned to MortSaver. It won't damage the phone-- just remove the program to return the phone to it's factory state should you wish to no longer use MortSaver. You can check it out here, and be sure to download the phone edition version: http://www.sto-helit.de/modules/edito/content.php?id=36 .
-------------------- Lisa Gade Editor in Chief, MobileTechReview