There are many good flight schools in South Africa. Good value and excellent flying conditions. Try FTS (Flight Training Services) in Johannesburg or Flight Training College in George. (wwwflighttraining.co.za)
43 Airschool in Port Alfred and APTRAC in Port Elizabeth are also good as well as Cape Town Flight Training Center.
As with any school, never pay all your funds upfront and check with the CAA regarding the schools reputation. That applies to any country you chose.
Best of luck. It's a great career. You wont regret it.