I personally used the Citikitty system (www.citikitty.com), but you can Google toilet training your cat and find a lot of tips and ideas that are free for you to use and adjust to your own needs.
Trust me, the time and effort it takes (which is really not all that much) will pay for itself over and over, once you stop needing to buy litter. Trust me!
I've never submitted a tip before, but am so pleased with my success and the money I've saved so far, I just had to suggest/submit a tip!
Source: Desperation, an idea, some research and ultimate success!
By Jarron from Ocala, FL