I wouldn't use the hovabator. As was mentioned they're designed to incubate chicken eggs. They have been used for reptile eggs, but they are known to dry out the air, so you have to keep your eye on the eggs to make sure they don't get dehydrated.
I would either make one yourself or buy one. You can use an insulated cooler; line the bottom with some 11" flexwatt and then place bottles of water on top of the flexwatt (for thermo stability). Here's a shot of one (2nd pic): http://cornsnakes.com/forums/showpos...36&postcount=4
You can also convert an old refrigerator into an incubator in a similar manner.