I posted this a month or so ago, but I figured I would add it to the sticky post to help anyone new to scripting KOTOR.
The command SendMessageToPC will print a message to the ingame feedback screen. The proper syntax is:
string cmMessage = "This is a test";
This script will print out "This is a test" in the Feedback screen. You can also print out variables, as long as you convert them to a string. It is also helpful to include the creatures name in your debug string so you know what creature is firing the script. Try the following:
string cmMessage = GetName(OBJECT_SELF) + "-" + "This is a test";
Or if you want a 1-liner:
SendMessageToPC(GetFirstPC(),"OBJECT_SELF's name is: "+GetName(OBJECT_SELF));
I hope this helps.