A water wiggler is a child's toy - you've probably seen them. It's a plastic tube/sleeve with water in it, and when you hold it the sleeve rotates and it slips out of your hand?
There's an example. They're pretty cheap, if you can find them. And, wowzers, that's a huge picture!
Based off information and lots of people here doing it, I just put some water in a small ziplock bag and taped it into a tube shape, rather than going all over town looking for some.
The point here is that then you can use those thermometers with the probe on a wire to get what the temperature is inside a simulated egg, as opposed to what the air temperature is in your incubator. You run the probe in through a ventilation hole in your incubator, and slip the probe into the tunnel in the wiggler, and there you have a probe surrounded by water that should reach the same temperature as an egg in the same environment.
My thermometer - from the cooking supplies aisle at WalMart - has an alarm that goes off rather insistantly (and at 3am, I might add) if the temperature gets too high.
Back to topic: My homemade egg turner is manual, but still a time saver. I cut the top off a 12ct styrofoam egg carton and cut holes in the bottoms of the cups. Then I cut a piece of 3/4" PVC to the length of the carton, and hotglued (I used the two-temperature glue and the lower temperature - don't blame me if the higher temperature melts through your carton) the PVC to the underside of the carton, longways. See below.
To turn the eggs, I just lean up the edge of the lid of the LG Still Air (which I added a PC fan to) and rock the whole 12ct of eggs the other direction. Lean, lean, lean ... three cartons fit side by side in my 'bator, and I'm done. I have my makeshift water-wiggler tied down to the carton in the center, and so can fit in about 28-30 eggs at a time.