A wonderful list of solar water heater ideas and installations. Time to start thinking about using the power of the sun to heat your water and save on energy costs.
http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm
The guy who runs this site is an retired engineer. He has info that goes way beyond solar water heating to solar space heating, solar PV, etc. no 'plans' per se, but he has plans for how he built all his stuff and tons and tons of information. you could easily get lost on this site for a week.