I wrote a quick and dirty LaTeX sparkline package last year to help generate some figures for a paper I was writing. Here is an example. I have been sitting on the code since last August, waiting for some time to clean it up and make it more user friendly. I finally decided to just release it as it is for now. It is pretty functional, but until I add some sort of automatic aspect-ratio detection, there is still some manual work to do.
Go to spark homepage to see it in action and download the package.