http://www.apple.com/mightymouse/

At $49, Mighty Mouse features the revolutionary Scroll Ball that lets you move anywhere inside a document, without lifting a finger. And with touch-sensitive technology concealed under the seamless top shell, you get the programability of a four-button mouse in a single-button design. Click, roll, squeeze and scroll.

Interactive porn possibilities! *tingle*

i tried to buy one today but it's sold out at my local apple store. thanks to the demand, i've saved $50! although, i'm afraid i'll just spend it when they are back in stock.