Volkmar Uhlig has written a nice application called VMware Serial Line Gateway. You can use this tool to debug software running in a virtual machine using the virtual COM port. The VMware Serial Line Gateway redirects the serial traffic to your host OS where you can catch the communication. First configure your virtual machine and add a COM port using the settings in the picture. 
The installation of this tool is pretty simple, just put the VMwareGateway.exe on your hard disk and run it in a command prompt, you have the following options:
Commands:
/T Interactive Testmode prints connects of pipe and socket.
/V Verbose mode for testing lots of printouts.
/R Registers VMWareGateway as an NT service.
/U Unregisters the Service.
/H prints a short help.
As you can see in the picture I started it in interactive test mode, now start a telnet session in Putty and make a connection to localhost port 567. After that log on to your virtual machine and start a Hyper Terminal session connected to COM1, you can leave all the other value’s default. When you type something in the Hyper Terminal it will show up in Putty.
Run as a service
If everything works fine you can setup the gateway as a service. Simply type vmwaregateway /r and start the service with net start vmwaregateway afterwards. Now everything works like before. The service is not enabled at boot time. So if you want the service starting automatically, you have to do that by hand. (Control Panel/Services).
