HOWTO Control Devices with the Serial Port and GUIs

One of the best and most concise pages you'll ever find:

http://www.pololu.com/docs/0J4?view_all=1

I'll probably use perl, but that's just me.

PC - windows - cygwin - gcc - Tcl/Tk

doesn't have to be a PC surely - linux ought to work. Except, then you have to be a guru to even get on the internet.