what do you mean by streaming via a dstv dish??
this could mean 2 things, either you want to use your dstv dish to connect to a ISP/internet? If so you need to find a Satelite ISP (i cant help you with this, but im sure someone on here, closer to home can

)
Or you want to stream your dstv content over the net? If so, there are a number of ways to do this, i use a slingbox, which is a simple box which connects to my Sky+ (uk satelite box) and in turn also then outputs to my adsl router, i can then connect to my slingbox from anywhere in the world, where i have a decent enough internet connection from either my laptop or cellphone, this allows me to control the box as if i was using the remote at home aswell
I have also tried the ORB application which works well. You need to have a tv card in a pc, near your DSTV (or in my case Sky) box. you basically plug your box into the TV card on a pc, then you need the ORB client installed on that same pc, you can then connect to your ORB homepage from anywhere on the internet and watch (or listen if you have a audio stream plugged into you pc) to anything that is currently being fed into the pc. The only downside to this is that unless you have a fancy (expensive) tv card which you can plug IR eyes into, you wont be able to change channels etc remotely
The slingbox has all of this, aswell as a built in Digital freeview reciever (good for about another 45+ uk tv channels)
One thing to note is that if you do this, it is going to eat up bandwith, and from what i have been reading on this forum, South Africa has a lot of issues with bandwith caps?? i thankfully dont have that problem (whew) i have been watching all the current ICC world cup games at work streaming at about 800kbps, and my home connection has a rather decent 1300kbps upload