If your looking for a useful serial port or rs232 terminal type of program then a great one for use on the Linux operating system is cutecom. Cutecom is a GUI interface serial port connection program that allows you to connect to your rs232 port and pass information. In my case I am connecting through that to my Amateur Radio Packet TNC for usage with the packet networks. Its straightforward to use, configuration is done from the same window as everything else and it has the ability to log the session to a text file and you can also append to the same text file for each connection session.
In all this has been a useful program for me, and I recommend it if your looking for a Linux Serial connection program.
I run Ubuntu, 9.04 and to install the application you would type from a terminal:
sudo apt-get install cutecom
it will go through the install process, when completed, to run the application just type cutecom