IP->Com is a freeware program to share all/any your COM ports remotely over your local network or the Internet, simultaneously.

IP->Com allows any of the existing serial (RS232) ports on your PC to interface directly to a TCP/IP network. This makes it possible for any other computer on the same network to send and receive serial data through a remote serial port on the PC where IP->Com is running. You connect to the remote serial port by connecting to a TCP/IP port.