Stay well away from this one. There are a number of bugs that when combined together result in the creators adsense code being served up most of the time and locking the owner out of their wp-admin. I believe this is an abusive plugin that should be removed from the WordPress Library ASAP.
Firstly, it includes a proxy script which allows the creator of this plugin to feed rogue traffic through your web server. There's no genuine use for this.
Secondly, as of the latest version, there's some bad coding (accidental, I'm sure *cough*) around the donation system which basically results in the creators adsense code being served 99% of the time - regardless of what value you enter into the donation box.
Thirdly, as if the above "error" wasn't bad enough, there's another bug which locks you out of wp-admin by serving a header() in a poorly (purposely?) chosen place. Meaning that even if you spot the fact that your site is now serving up someone elses adsense, you can't get in to fix it without connecting via FTP and deleting the plugin.
Absolute shambles. Stay away from this plugin.