While full on solar water heating is becoming more and more affordable, and may soon be available easily to the average do-it-yourselfer, it's not the only way that you can cut energy consumption from hot water. If you've got a backyard pool, or belong to a club which has outdoor pools, consider the energy saving potential of the Belvisi Solar Shower. It 5.5 gallons of water heated in an internal reservoir using solar energy. When you want to rinse off from the pool, you adjust the hot/cold mix for the perfect temperature -- up to 130 deg. F! That's hot enough to make even the most jaded water-heater junky take notice. Solar heat can be yours for around $250.00 US.
:: Belvisi Solar Shower at SolarDirect :: and at Hammacher Schlemmer [by DM]