I went to Cape Town in 1994 (soon after Mandela took office). It was the best trip of my life. Before I went, I wrote to the South African Embassy (in New York, I think), and requested any info they could send. They sent me a ton of very helpful brochures, booklets and maps.
Make sure you do some of the following things:
Get a hotel (like the Cape Sun) with a room facing Table Mountain. Spectacular view and the staff at the hotel was wonderful.
Go to Green Market Square - excellent Flea Market and bargains galore - the exchange rate was 3.64 when I went - now it is over 7.00!
Take the cable car to Table Mountain. Breathtaking views.
Take one of the all day tours offered by the hotels that will travel down to very tip of the Cape. Excellent wildlife (although not a full safari), and the tour guides were friendly and informative. The tour I took also went along the coastal towns and to the Stellenbosch winery.
Take tons of pictures - and make sure you get them developed before you leave. That way you have a chance to go back and try and get the photos again if they didn't turn out.
So much to do and see: go to the beaches, parks, V&A Waterfront, and above all - talk to the people. They are all very friendly, and are great sources of info. I am still friends with people that I met in SA in 1994. However, don't get the wrong impression - all is not rosy in South Africa - it has one of (if not the) highest rape rates in the world, and carjackings are commonplace. So, use precautions you would use when traveling in any country (don't flaunt money, expensive jewelry, expensive cameras) and have a great time!