Expat Arrivals offers a section which includes much useful advice on moving and living in South Africa.
Expat.com is a worldwide directory of blogs related to expatriate life, with listings for South Africa.
Welcome to South Africa is the official South African Tourism website.
Lonely Planet Worldguide provides a lot of useful travel information about Africa in its Explore Africa section, including South Africa.
Rough Guides Destinations offers much useful travel advice and information for most countries, with a section on Africa, including South Africa.
BookMundi: Things to Do in South Africa offers a nice summary of options for a trip to the country.