Imagine never having to clean the cat litter box ever again. While the benefits of potty-training your cat are obvious, it takes time (average 3 to 4 weeks) and patience. Your cat's behaviour will have to be modified slowly and gradually so that it will not get upset by the change.
If your cat is already using the litter box, then your potty training task is that much easier. Otherwise, get it to use a litter box by placing some litter in a container. The litter should ideally made of a easy to cut material such as foil or cardboard. Put your cat and the litter box in a small and quiet room with low traffic. Gently place the kitty in the litter. If it jumps out, try again in awhile. Do this for several days and the desired behaviour of eliminating into the litter should be cemented.
Now that your cat is familiar with using the kitty litter, you can begin potty-training. Start by moving your cat's litter box near a toilet and let it become familiar with the new location.
For the next few days, move the litter box inch by inch towards the toilet bowl.
When you reach the toilet bowl, leave the litter beside the toilet bowl so that your cat will associate the toilet bowl with the need to go to the toilet.
Then, gradually raise the litter off the ground bit by bit (add height with magazines or newspapers) until the cat gets used to jumping onto the litter to the height of the toilet bowl. This will take a couple more days.
Subsequently, move the litter box such that it's sitting directly over the toilet seat. Secure it with tape or tie it down so that it will safely hold the weight of your feline.
Cut a very small hole in the centre of the box, increasing it gradually. Similarly, decrease the height of the box bit by bit until eventually, there is no brim left. The amount of litter should also be decreased gradually until the box is empty. All of these should be done consistently but slowly over the next few days.
Give your cat a few days to adjust. Remove the litter completely and you will have a toilet-trained kitty.