Google Code FAQ:

The Google Chart API is an extremely simple tool that lets you easily create a chart from some data and embed it in a webpage. You embed the data and formatting parameters in an HTTP request, and Google returns a PNG image of the chart. Many types of chart are supported, and by making the request into an image tag you can simply include the chart in a webpage.

Check out this little “Hello World” sample:

http://chart.apis.google.com/chart?cht=p3&chd=s:hW&chs=250x100&chl=Hello|World

I don’t know how long this has been around, but I found out only a week or so ago. The Google Chart API will be very useful for me in a bunch of reporting projects.

If you are into Ruby check out Ruport (Ruby Reports) and the Online book I found online.

Via Google Code