Look on Aminet, there are loads of GUI creation tools.
The most notable ones probably are AWNPipe and MuiRexx.
AWNPipe is a pipe-like device which allows to create a GUI using ClassAct (or ReAction on OS3.5+). It can be used from any scripting language because it is operated by smple read and write commands. You can even use the Echo command to create a GUI.
MuiRexx lets you create a MUI GUI from ARexx. It is probably the most powerful tool.
Bye,
Thomas
