alert every time user connects to share

Hi,
I’m looking for a small and good utility, which will warn me every time a user connects to my pc (through netbios, tcpip,…) to for instance read my shared folders. I mean something similar to the standard windows “netwatcher”, but something that continuously checks if somebody is connecting/connected to my computer.
I’ve got ZoneAlarm Pro, but I can’t seem to find this feature within this program.
I’d like something small which is configurable and running in the system tray, and which does not use up my cpu.
Thanks.