"xAP Desktop simply put is a desktop information display system with the ability to control systems as well as display information. Using floating windows, dynamic wallpaper, transparencies, fading windows, etc it displays information in as rich a format as possible whilst trying to keep out of the way of pc usage. Every element of every display can be changed as each is based on simple text files as well as allowing all the elements to be based on xAP data."
Guides for setting it up here
Guides for setting up caller id display here
New to Desktop? here for an overview and screenshots