Changing color in GLSL

How can i write a python script to change color in GLSL as you do in Multitexture,

for example in multitexture:

import bge

        def main():
   
        cont = bge.logic.getCurrentController()
        own = cont.owner

        space = cont.sensors["space"]

        if space.positive:
             own.color = [1,0,0,True]
        else:
             own.color = [0,0,1,True]

main()

i know this changes the object color but how could i do this same thing using GLSL?

thanx in advance

Tim

Make sure you have object color enabled in your material settings.

Thanx very much!