The Google Chart API lets you dynamically generate charts.
The Google Chart API returns a PNG-format image in response to a URL. Several types of image can be generated: line, bar, and pie charts for example. For each image type you can specify attributes such as size, colors, and labels.
Check out how to use the new Google Charts API here - http://code.google.com/apis/chart/
Check out the following samples. You can right click on the images and see that the graph data is embedded in its URL itself.
Check them out !!