I have a programmable thermostat and love it.
You can find them at any Home Depot, Lowe's, or hardware store. They replace a regular thermostat, one where you manually turn the temperature up and down.
With the programable thermostat you set the program to turn the temperature up and down automatically throughout the day. Mine goes down to 60 at night (I like to sleep in a chilly room and my orchids seem to like it). In the morning it goes up to 70 right before I get up. Then it goes back down while I am at work returning to 70 before I get home. Most of these thermostats have multiple settings throughout the day and can be programed differently for different days of the week. They aren't real expensive. I've seen them in the $20-$40 range. I also have noticed that they can be used with A/C if that is controlled by the same thermostat. I don't have any experience with A/C settings as I've never needed it up here.
We replaced our regular thermostat with a programable one 6 years ago. It was quite simple to do and didn't require an electrician or any special tools.
Hope this helps.