This tool allows you to generate graphical charts based on data you can export from your Google AdSense account. You can create multi-dimensional charts with seperate plot lines for each channel if you wish.
Update July 2010 - the new AdSense interface that Google has been testing for the last year is now available to all users. The new interface now has very nice charting functionality (hello, 7 years late... heh), so this tool is no longer needed.