This is a great solar water heater conversion that I found on the net. They also sell on eBay and it is a really great product. Modular design so you can add panels on the fly and taylor you heat ouput accordingly for a fraction of the price or the space of conventional solar water heaters. The great thing about it is that you can use your existing gas or electric water heater so it saves on materials, wastes nothing and saves a lot of money. I hope you folks like it as much as I did. It was really easy to install and they have a wealth of pictures, documents and videos showing the easy installation.
To look at the solar water heater go to http://www.heliatos.com
This next link is for a solar water heater I almost purchased which would be quite good and perhaps more efficient? http://qddsolar.com/