var shader1 : Shader = Shader.Find( "Diffuse" );
var shader2 : Shader = Shader.Find( "Transparent/Diffuse" );
function Update()
{
if( Input.GetButtonDown("Jump") )
{
if( renderer.material.shader == shader1 )
renderer.material.shader = shader2;
else
renderer.material.shader = shader1;
}
}