Well, I got it - but I have a few questions.... Where could I set how quickly I want this animation tu run? Where could I set if I want loop animation or let it run only one time? I cant find anywhere buttons for such a things... And when I start preview animation, my Blender completely get mad. I can see this color-changing render window, but its impossible to stop or close it and continue work. All I can do is close all Blender - it isnt very well, is it?
Everything will go wrong, anyway - then, why to be pesimist as well?
Actually, you don't have to render the animation to see the color changing. You were fine as far as inserting RGB keys, but instead of rendering the animation, do the following.
1) Switch to Texture Mode.
2) Press Alt-A if your cursor is in the 3D window, or Alt-Shift-A to make all windows animate. You should see the cube changing color in the 3D window.
I have a question, How can you get the color animation to work in the blender game engine? I've set up a fuel meter in the game I'm working on and have it animated to decrease in size. I also have the color change added to the meter,(which is just a plane animated for scale on the x axis.) when I use the ipo time line and animate the object, the object both changes color and scale, but when i put it into the game, only the scale animation works. the color does not change in the game even though it's added to the ipo animation. I can't seem to find any additional options for adding the color in the game engine ipo actuator.