Development here is mostly focused around consuming & adding to technology - e.g. CRUD apps, although there is a small population of startups. Cape Town has the Silicon Cape initiative and there are a couple of incubators in other cities, e.g.
http://www.theinnovationhub.com/I have no idea how many developers-in-garages there are. I've watched the Business of Software forum, ASP and a couple others, but haven't sensed many other South Africans (or Africans). There is some interest in the social media area, like Afrigator.com and a few service-oriented companies. During the .com era, there was something called First Tuesday, which mirrored an overseas initiative of the same name. Meetups of ideas/money/services first Tuesday of every month.
In terms of bigger names...hmm. Alon Musk was born here but not sure when he left. Mark Shuttleworth started here. There's a make-a-site-easily company that is doing well but whose name I forget (edit: yola.com), and they're now in California.
Ah - here's an index:
http://www.sastartupindex.co.za/
Maybe there's a startup idea in there :) /adds to list
