So AT&T just announced the new data plans – $25 DataPro with 2GB data included and $15 DataPlus with 200mb of data. Do I need to change my unlimited iPhone plan to the new $25 plan? If you are an existing AT&T customer and already enjoy unlimited data for $30, you don’t have to change anything unless you are very sure that you won’t use more than 2GB a month and want to save $5 a month. One thing I should warn current iPhone 3G and 3GS users – once you update the data plan you won’t be able to undo it. If you are watching YouTube and streaming music/radio regularly, I strongly suggest you stay with the unlimited data plan. Of course, for those of you who are use data occasionally, you should definitely change to the DataPlus plan – that will save you $15 a month.