I want to make a text box in .NET \"glow\" yellow, and then \"fade\" to white (basically, by incrementally increasing the brightness). I think Stackoverflow does this after you\
Just interpolate between the colors based on the time.
If your orange color is (r1,g1,b1) and you wish to fade to a different color (r2,g2,b2), the formula for linear interpolation is (r1 + (r2-r1) * t, g1 + (g2-g1) * t, b1 + (b2-b1) * t), where t is in the range of [0.0 1.0].
In your example, your first color is probably something like (255,200,0) and your second color would be (255,255,255).
If you wish for smoother transitions, look up different ways of interpolation.