Google Adsense program could soon be integrated with Google Analytics to track visitor clicks in Adsense Units. This was revelead in an email from the Google Adsense Support team.
While Google Analytics is certainly still useful for tracking your website performance data, at this time it isn't able to track your AdSense clickthrough data, nor is it integrated into your AdSense account. We're working hard to add new functionality as quickly as possible, but are not able to say at this time whether an integration with AdSense will occur.
I am actually exploring different methods to track visitor clicks in Adsense units. Google Analytics looks like the best available option to track visitor clicks since both the products come from Google. And Google has clarified that it would not violate the AdSense Terms and Conditions to use Google Analytics to track outgoing clicks.

With Google Analytics, you can track clicks on links that lead away from your site. This technique can be extended to track the Google ads that are being clicked, on what page they are being clicked, and who is doing the clicking. Because these links do not lead to a page on your site containing the UTM JavaScript, you will need to tag the link itself with the urchinTracker JavaScript.

The following Google Analytics Adsense click tracking javascript should be inserted after your Google adsense code. It will loop through all of the IFRAME on the page, and if the IFRAME source includes "googlesyndication.com", it will attach the function asClick() as an onfocus handler. When the ad unit obtains focus, asClick() will check to see if the status bar contains either "go to" or "View ads about". If so, urchinTracker() is called, with a page identifier that includes the ad type (ad unit or link unit) and the ad or link text, as shown in the status bar.



If the above method sounds a little complex, you can try adsense clicking scripts that work with PHP, ASP or VBS. But you need access to the webserver since all these script require a external database to store click tracking data.