As far as I know, there are no programs to prevent click fraud. Just don't join any scammy "make easy money" programs like EasyPPCMoney and things like that. They are sure to get your AdSense account banned. Also, don't give out your website URL; not even to your family and friends. Let me rephrase...ESPECIALLY not to your family and friends. They'll think they'll be doing you a favor by clicking on your ads a bunch and making you money, but Google will detect this as click fraud and can potentially ban your AdSense account. So just play it safe, and don't do anything to raise a red flag in the eyes of Google!