I for one, wouldn't put a bird and an adult cat together ever, specially not unsupervised (this is meaning playing out of the cage, as I know you see on Animal Planets Funniest Animals). I feel this can just be too dangerous.
I have owned 2 keets and a bunch of cats at the same time. I currently have one keet and 3 cats. All 3 of my cats would love to kill, if not eat this bird had they the chance. Yet I had another cat, who was basically a barn cat she's the one I will refer to as "The tamest feral I've ever met" lol. My first keet and this kitten formed a type of "friendship" through the bars of the cage. This cat never tried the hurt the bird as the others do, when the cat would jump next to the cage, the bird would come over to that side and try to sit next to the cat, and would talk to the cat. Mind you this was after the cat allowed the bird to bit paws and noses until the bird felt the cat wasn't an enemy any longer.
My best advice to you, is to just keep the bird out of reach as much as you can. Either keep the bird and it's cage in a room behind a closed door, which the cat will never have access to. A lot of people say that birds get too stressed out from the co existance of birds living with other animals and that they will die or fall very ill. While I wont flat out deny this, I can say I have never seen this, my birds and my clients birds who live with other animals are very happy and healthy animals, whom have actually gotten used to the presence of the cats/dogs/people, etc.
If you don't have a room, susupend the bird from the ceiling, away from any furniture where a cat could jump to the cage. Bird love sun shine, so try to hang the bird in a room with a window, but just mind any excessively cold drafts from the window or excessive sunlight.
It's possible there is cats out there who have been successfully trained to not bother the bird, but I can tell you my gang is not one of them! While it's not their all day target, they do try to get to the bird now and then.