Microsoft unveiled their latest mouse today, the oddly named IntelliMouse Explorer (thanks Quiller). It's a wacky looking thing with four buttons and no moving parts, and will be available in September. Here's a snippet from the press release:

The most significant improvement is the addition of Microsoft IntelliEye, an innovative new optical tracking technology that makes mouse balls and pads seem as archaic as the dot matrix printer. An optical sensor captures images of the work surface at a rate of 1,500 images per second, and a digital signal processor (DSP) translates changes between the images into on-screen movements.

This technique, called image correlation processing, results in smooth, precise pointer movement. The mouse works on any surface - paper, walls, your jeans - no mouse pad is required. And since the mouse has no moving parts, cleaning is unnecessary; after years of use, the IntelliMouse Explorer will be as responsive and accurate as the day it was purchased.