Logging on PDA's

Question

hi, I developed a program for da PDA which counts the open windows all 5 seconds and writes the titles in a XML FIle. i developed it for usability tests in order to see what the user do. Do anybody know further ideas or extensions to my program to get further or detailed information about the tasks and/or commands a user executes? this would be very important for me because i need it for my diploma (thesis) thanks in advance. yours sincerely, patrick