I use a script called Adsense Tracker to track my Adsense Clicks. (It also works with YPN.) It's part of a package called Adsense Gold. The rest of the package is not particularly valuable but the tracker is worth the entire price. You can see it here (not an affiliate link):

Adsense Gold

The script uses a mySQL database and the setup is pretty straight forward. It logs clicks by the hour. It also tells you what ad the person clicked on and what keywords generated the clicks. I use this for:

1. Finding out which content attracts clicks and then adding to it.
2. Finding out if there's an affiliate program for an ad that gets a lot of clicks.

The script will also tell you which pages and ad formats get the clicks. Very useful info. You can use it on every site you own.

Cheers,

Rich