Help me in domain parking

I have a website that I don't want to develop anymore. But I still have about a year before I have to renew my domain name. I registered my domain on speedhost. I was surfing on internet when I came to know about domain parking. One thing that I understood is that it is like giving your domain name on rent where only ads will shown. Looks like a good way to earn money by doing nothing.
Please guide me how do I earn money by parking my domain without spending anything.
Thanks