How/where do I download free games for my Nintendo Wii?

I only have two games for Wii right now, including the free Wii sports it comes with. I've had my Wii for years now and think that I would play it alot more if I had more games for it.

How exactly do I get these "Wii points" I keep hearing about. How do I get free games for my Wii? And where?

Thanks in advanced.