My daughter didn't have night terrors, but she would walk and talk in her sleep. One thing that really helped, and I've heard it helps with night terrors too, is an Epsom salt bath before bed. Magnesium gets absorbed through their skin, and that is what helps. You can also try magnesium supplements, but I haven't had to do that.
If you're interested in trying it, just pick up some Epsom salt in the pharmacy area of the store and start off with about 1/3 cup in the bathwater. Each night add a little more until you are up to 1 cup. I've heard that at first it can make the child a little hyper, but that's just more proof that they are magnesium deficient. That's why you start with the lower amount. My daughter would go weeks without sleepwalking, but as soon as we'd get slack with the salt baths you'd know right away because there she would be, stumbling through the house in her sleep.
Good luck!