Writing a Script to capture login and logoff on a network pc w/windows xp

I looking for assistance in writing a script that can capture user login and logoff times and configure the box to send an e-mail to user utilizing smtp. All the boxes have windows XP service 3 loaded on them except for two that are still using Windows 2000 professional. There isn’t a domain controller and/or windows server box available to capture login logoff time stamps.