Checdk To See If Someone Is Connected

I am developing a small program that is going to be accessed by no more than 10 people in an environment with server 2003 and most stations running Xp pro. Our existing app is a console c programmed one from '92. My plan is to have the new app being vb6 frontend and backend access 2000. The program is designed to leave staff member little notes internally.

When someone logs on they will be given their messages (stored in an access database). How can i open the database display the info if someone else needs to log on at the same time. Is this a checking routine  - any suggestions for links to appropriate coing standards. As alswways, thansk