I did my training at Rand Airport. Try:
- Sky Raiders (www.skyraiders.com) - they have plenty of well maintained aeries and friendly instructors who are always available. Good flight school.
- U-fly (www.uflyacademy.co.za) - Know the owner very well. Top guy and good school.
- AFOS (www.afos.co.za) - They use tecnams for training which is cost effective. Hear good reviews about them.
Also try Grand Central:
- FTS (www.fts.co.za) - Have a mate that works there, haven't heard anything bad.
Those I would recommend you have a look at and get quotes from. They are, IMHO, the best at Rand and the only one I know anything about at Grand Central. Rand is also centred mainly around training and there isn't the worry of 737's up your tail or extended downwind for 15 miles or waiting at the holding point for 20 minutes (not normally anyway)...
Other than that just google - Flight schools at Rand Airport/Grand Central/Lanseria and youll get lots of hits.
I am not promoting any school this is just from my experience and is my opinion.