Hi Janette,
I've heard it's quite difficult for South Africans to acquire British citizenship unless one of your parents or grandparents was born in the UK. have a look at the Work Permits page on www.expatarrivals.com it has some useful info about the new points system that the UK has put into place. I'd say that it would probably be easier to get a job in the UK and live and work there for four years and then apply for UK residency...once you've got that you can try the citizenship route.
Good luck :)