Animation on your desktop? You can create a movie of an animation and have it play on your desktop, if that is what you mean. You do not need any coding for that, it is the same as making any animation in Blender: see the Blender wiki here http://www.blender.org/education-help/tutorials/
. The only thing you need to do once your movie is made is to get it to run as wallpaper, if that is what you mean. I am sure that if you look on the net someone will have a small free screensaver thingy that will play your animation on the desktop - without knowing what operating system you are using there are too many possibilities to list here.