There are many places to stay in South Africa - Accommodation ranges from 5 star luxury hotels, guest houses, lodges and back packers. Again one will have to be very careful when choosing accommodation.
I suggest you stay no more than 10-15 km radius from each stadium. Traffic is an absolute nightmare in SA it can take about an hour to cover a few kilometers in peak hour traffic. They are busy building special lanes on some of the freeways to accommodate the traffic.
I will try to locate links to accommodation within the radius of each stadium. There are people here wanting to open their homes for the duration of the World Cup. This may be an attractive alternative than staying in hotels and guest houses.