Hi
I have a membership - Happy to search a few records - the records on this site are transcriptions of original documents and may have errors. They also have some family trees of prominent South African families.
You can also look on the NAAIRS site for the archive where the records may be found, unfortunatelly they don't index the births and marriages but the death records are indexed. .
The site also has transcribed several bboks - like "British residents at the Cape" and so on.
There is also a mailing list on Rootsweb where someone is trancribing the birth, marriage and Death notices from the South African Advertiser that may be useful - you would need to know which year so you can browse the various transcriptions.
Cheers
Gillian