Here are two places:

http://www.biogreen.co.za/ - I think, they are now national.

And here: http://www.green-diesel.co.za/

And if you want to make your own: http://www.green-diesel.co.za/processors/

Must admit, after seeing the mess that surrounds the process of making Biodiesel, all which is perfectly normal, making my own does not fit anywhere in my realm. 

How to get in contact

Did my own many years ago with a small plant. Ran in a Nissan Sani...

Making your own is a lot of work and a bit tricky, so eventually started using a cheap provider to get rid of the workload and the waste product that wasn't as easy to get rid of as expected... There is only so much soap you can make and sell at markets!

The good was that is worked out quite cheap to run a hungry Nissan 4x4 with 80l tanks, but the bad was that if it wasn't perfect, then it would fail in low temperature environments (Winter in the Drakensberg). Even running a mix was not a match for freezing temperatures. Note this was only because it wasn't 100% correct and almost handmade, it also performed great in Durban where temps almost NEVER get below 4 degrees.

It was good fun, and saved a few bucks, but eventually realised that would save more money making my own beer - he he.

Also investigated Butanol for Petrol replacement - Absolutely perfect replacement, but in SA the cost exceeds Petrol price since all made by Sasol from petroleum sources instead of Bio sources. A 1988 VW Passat was an awesome test vehicle and could not only keep up, but beat many modern cars (admittedly the hardcore conversions were made before switching to Butanol). But being able to race a 2009 BMW 325 and beat them in a 1988 Passat, was definitely awesome. There is no power advantage with Butanol, it almost behaves the same (depending on the vehicle and timing it may have a slightly lower bottom end torque or a slightly higher top end speed, the same as adjusting timing/mix on any other car).

Now that I have ranted, my suggestion for BioDiesel is to find a reputable supplier rather than buying the expensive equipment. You will get the fuel cheaper but without the headaches. Quality BioDiesel definitely works and is economical, but your l/100km will be about the same.