First you need to decide if you want to use the WiFi capabilities of your computer. This is a great plus (frees you from cables) but does add costs. A reasonable WiFi router will set you back around R600 to R1000 depending on make and retailer. A WiFi router can be coupled to all the options mentioned below EXCEPT 3G/HSDPA. The vodacom/MTN service needs to be coupled to a SPECIAL Linksys router which IF you can get one will cost around R2500.
ADSL - Reliable, fast, cheapish but not portable and it will take you 3 weeks to 3 months to get a line installed...Short term or long term contracts are available depending on ISP.
IBurst - Depends on locale (get an on-site test done by someone who knows what they are doing) but is generally reliable, fast, cheapish and portable and can be setup in a matter of a few hours. HOWEVER being wireless, this service has higher latencies than ADSL so not great for online gaming and VoIP. IBurst is THE wireless competition for ADSL. You can get month to month or 12, 24, 36 month options.
3G/HSDPA - Also depends on locale but is fairly reliable, fast to very fast and can be acquired quickly. Works overseas too (though there are additional costs for this) but you will need the USB device (hard to get). Also this service is cheap on the low end but VERY expensive if you start using more than your limit or if you go for high end packages (eg 1GB plus). This is an option for the guy who does a bit of work so doesn't require tons of bandwidth and needs mobility. 24 month contracts are order of the day here (month to month is not worth it).
MyWireless - don't go there at present.
That is really it. There are some weird and wonderful other solutions but some are illegal and some don't work that well and are generally only worth considering if the above solutions won't work.
Hope that helps...
