My kitty that we got on 11/10/07 made quite a few hiccup noises especially when we first had him and right after eating. He's now 7 months old and seems to make a little less noise. lol
Mine are going on 10 months now and although the hiccups aren't as frequent as when they were younger, every once in a while one of them will jump in my lap and will have the hiccups. Doesn't seem to phase them though.........both of them just sit there with their eyes closed.