I've done some research, most of the markets work in pretty much the same way.
Android Market - now "Google Play" charges you a once off $25 fee to register on the market to release free or paid apps. You're required to use Google Checkout as the payment processor where they take 30% of your sale. However, Google Checkout does not support payment to ZA banks at this time. There are lengthy and potentially expensive workarounds, like registering a US or UK company and obtaining a bank account in the same country. Alternatively, find a publishing company that can publish for you. You will probably lose more income with this method though, and you have to watch out for the publisher T&C's, as some of them actually take ownership of your work (Hyperbees!).
Amazon Appstore - Free for the first year, $99 per year thereafter. Takes 30%, and CAN pay out to ZA.
Windows Marketplace (For Windows Phone 7) - $99 per year, can publish as many paid apps as you like, limited to 100 Free Apps. Beyond 100 it's $19.95 per free app to publish. CAN pay out to ZA.
... as an aside, oddly enough the same subscription gives you access to the XBox Live Indie Marketplace, which does NOT support payments to ZA or the ability to submit games from ZA. Go figure.
... and Apple we know now too, definitely no thanks to them. So they have moved to the back burner as I don't have the funds to buy Macs for dev purposes and test devices, and still have a bit of a sour taste in my mouth after their crappy response.
Forgot to add that in dealing (selling) with these US based market places, you will need to register with the IRS in order to get a Tax Identification Number, and fill out forms etc... OTHERWISE your payouts will be subject to a 30% tax withholding, which you will have fun claiming back from the IRS.
It seems to be a relatively simple process to register though. Note that South Africa has a tax treaty with the USA to avoid double taxation. So your income via the US markets will be tax exempt (provided you fill out the appropriate documentation), however you will still need to declare it to SARS and pay tax on it here. For business the tax starts at 7% up to a max of 30%, I guess depending on the amount concerned or rather annual income of the company (AFAIK).
