There’s a free tool called SynSense (http://www.singerscreations.com/RSS/Posts/235.asp) which is more of an AdSense monitoring tool. This sits in the tray and offers actualized AdSense stats as you hover your mouse over its icon. It’s a very nice tool for those which like to be informed on how their AdSense is doing at all times of the day.
Google provides you with stats in a csv format on their site. So someone made a tool that can automatically download such files and extract a lot of information from them. The name of this tool is CSV AdStats and it is available from http://www.nix.fr/en/csvadstats.aspx?q=download
It has a large number of features, including the possibility to highly customize reported stats, exporting data and charts to other formats. It’s in French but the language can very easily be changed to English.