whats the best way to do this?

Hi,

I have an accounting department downstairs and an HR department upstairs.

I need to create a program that will send a notification from accounting to HR to let them know a process is ready. Then HR would send a nofication back down to accounting throughout the day.

The trick is - can't use email for this.

I would like to somehow pop up a little form on the middle of screen for the appropraite users - saying "Phase 2 of Payroll has started" etc.

Don't know the best way to do this...