If you got the iPhone Simplicity plan, the unlimited data should be enough since it caters specifically for the iPhone. At least that was the case for the 3GS.
Yeah. Where it says on o2s iphone page that intially your on txt/web it also says u can switch tariff once a month, and there was a link taking to you the tariffs and thats where the simplicity tariff is, so should that be okay then?