Too bad you need to jailbreak the ipad to do it
in reference to:
"Using the BTstack application that brought Bluetooth mouse support to iPhone, enterprising individuals discovered the same technique works on a jailbroken iPad as well, and hooked up Apple's own Magic Mouse to show it off to the world. Mind you, while this implementation does look quite useful, we do detect the barest hint of lag"
- Magic Mouse syncs with jailbroken iPad, enabling cursory cursor control (video) -- Engadget (view on Google Sidewiki)