Answer by Rory Young:
FGASA is the Field Guides Association of South Africa. Their system has various levels and grades and covers the private sector only. Walking is also not a common activity in SA and in the National Parks is only undertaken by Parks rangers. Therefore courses offered in this system can vary hugely.
The only organization I would confidently recommend in South Africa is.
Zimbabwe has a gruelling 4 year licensing system based on a mentorship/apprenticeship program combined with examinations and proficiencies under the Department of National Parks and Wildlife Management. Here is a recent article on it:
Zimbabwean Professional guides are licensed to walk in the National Parks and approach dangerous game on foot and armed.
Unfortunately although by far the best, the Zimbabwean system is open to citizens and permanent residents only. I am currently busy, together with the director of training for the local guides association, revising and expanding the training material used to train guides in Zimbabwe. If there was enough external interest we could offer the program to foreign residents but they would not be able to get the license. To do four years training would be unique experience but would be a bit crazy to not have the license at the end of it.
If you seriously want to make a career of it then I would recommend SAWC. If you would like to enjoy the experience then I would recommend either a short course with an institution such as SAWC or volunteer work with one of the well known NGOs.
The best way to explore African wildlife and nature is to be guided by a professional guide on foot. That way you get a realistic impression of the wildlife unlike a vehicle and you don't miss all the smaller animals, plants and of course the tracks and signs of the bigger animals.