Build Solar Water Heater

I saw an episode in extreme makeover home edition were they built a house for a family and they used solar energy to power the house I like that not just because is good for the envirorment but because I think is better for us too, If we take care of the Earth we live in I think is going to last more.

Besides thermal and electrical energy, what can solar energy be converted into? Please post your reference if you have one.

Dear All,
How can I calculate how much energy converted from Solar Energy to Electricity? Does it based on the how strong of the sunlight? Does it based on how many solar cell? Any detail equations for this purpose?
Thanks a lot.