We have an iron fence and gate. The bars are pretty basic, they're smooth and they go straight up and down. We put it in at both houses, we bought it at Lowes. It was expensive though. I don't remember what we paid at the old house, but at this one, it was $300 to just go about 20 ft. They're indestructible and never need to be painted though, so I guess it'll pay off in the long run.

One thing to keep in mind...put the latch on the opposite side of the dogs. Roxy figured out how to stand up on her hind legs and open the latch with her paw.

*edit* Two sides of our fence are wood, like PITC's, and the back is a brick wall. We just put the iron up to divide the yard, it's kind of like a big dog run.