Move files automatically when created

Is there a utility that will move a file to a different location as soon as it is placed in a folder? I am trying to find a more efficient way than my program which does the following:
1. In runs all the time.
2. It looks into Folder A. If a file is located in that folder, it moves it to Folder B, leaving Folder A empty.
The reason for this is that I am receiving files through a modem at different times. I need those files available to other users on the network, but I want the externalsource to place it on the workstation which has the modem. I do not want to grant the external sender to have access to the LAN.