DoodleDesk, the “whiteboard for your desktop” from Imaginary Roots, is now available on the Mac App Store in the Productivity category. It requires Mac OS X 10.7 (“Lion”) and costs US$5.99.

DoodleDesk replaces your desktop background with a whiteboard where you can draw freely and add text notes. The application provides you with three colored pens, an eraser and a notes tool

DoodleDesk works by replacing the desktop background with a whiteboard surface, giving the user a platform to get their ideas down in a location that’s always accessible from the systemwide show desktop hotkey, according to Imaginary Roots founder and lead developer James Griffin. When it’s not being used, the whiteboard sits behind the desktop icons, so the computer works as normal. When activated, either from the dock or by alt-tabbing, the application comes to the foreground and the whole screen is available for drawing on.