Technology has come a long way in the last 20 years and the drive to save energy has never been stronger. Solar energy and wind energy are being looked at with renewed enthusiasm as people are more interested in preserving the environment than ever before.
But since you came here looking for a solar hot tubs, why can't you find any dealer that sells them? The reason is because nobody makes them, even in 2011!
You see, there just isn't enough demand for them as you need to live in a place that gets a whole lot of sun. Most people leave their hot tubs on all the time to keep it heated as that is less expensive than reheating it from scratch all the time. Of course, during the dark winter months there are very few places in America that get that much light.
The best you can do right now is to buy some sort of a solar panel hot tub kit and make your own. If you have some technical ability you might be able to buy solar panels on Ebay or some other place and construct your own solar powered hot tub that would at least help a little bit with energy savings. But as for a full fledged solar hot tub straight from the manufacturer: they don't exist.
Other than constructing your own, you should of course buy a good solar hot tub cover to help keep in the warmth. The better your cover, the more energy you will save. You may also want to place your hot tub in a protected place so that the wind does not hit your hot tub or jacuzzi straight on. Wind can be a severe cooling agent and you want to avoid it to save on your heating costs.