Folder Notification

I have recently installed an Hp proliant G2 file server to my network giving me the ability to restrict folders to those who need them. Excellent.
What I really need now is when certain directories have new files put in them that it sends a notification message to the relevant people/department. I have a spare email address I can apply to the server. Is there any way i can achieve this without spending money? Tge I.T budget is as tight as a snare drum. Oh the joys of working in the construction industry!