At the moment, I'm only using on wifi. At home, I've got uncapped, so I don't really care how much data is being used.
My friend made his own 'mini-sim' by using the AT&T sim, that comes with the iPad, as an example.
Hey
I would suggest getting yourself an US account on iTunes. The South African iTunes is quite limited.
The SA Sims do work, but you need the mini-sim (That is only available in September from Vodacom).
I got the 3G 64Gb one and I'm smiling all the way! :)