How to read a mouser optical led?

I've been told that new PC mouse technology revolves around reading either a led (optical) or possibly a laser led....I don't know if this is true, yet the dpi are truly impressive. Have any of you tried to read a mouse led (optical or laser) into an application that would give a linear output? You figure that if you can slide a mouse around on a piece of paper and get super accurate results, why not be able to set up a laser equipped mouse and do a super cool linear reading of something passing in front of it??? I'd do the electrical/mouse hookup here at home and try out anything you all can come up with.