I happen to know someone in AVIVA and have a relative who did volunteering through AVIVA. Therefore I would recommend that anyone wanting to make a difference or add volunteer work to their CV consider AVIVA. See their logo for the website.
AVIVA have a wide range of volunteer options from working with wildlife, to nature conservation through to learning new skills with children in need or spending time with abandoned babies and children.
You could get up close and personal with a lion, learn to surf, tag a penguin, teach a child how to read or end up falling in love with an abandoned baby. What you will do is make a difference and leave South Africa a better place for your visit.
AVIVA arrange airport transfers, accommodation and they have their own tour bus and shuttle bus so you get to see Cape Town as well. Both accommodation centres have housekeepers as well as laundry and catering facilities. People come from all over the world, are of all ages and all walks of life. Lifelong friendships are formed and some people end up staying far longer than they intended. Many come back year after year.
If you happen to drive into Cape town and you see the huge white dome on the foreshore with Zip Zap circus written on it, that is where children in need are taught to circus arts. Now how cool is that!