When you browse the web or download an app you generate data usage on AT&T's wireless network. This figure of 2GB or 200MB is the amount of data generated AT&T will let you use. Lets say you have the $15 200MB plan a month. Well, when you go on the web browser, the page will be downloaded from the internet and sent to your phone. Since you just went on the internet and downloaded a few songs and went on youtube you now have 192MB left to use for the rest of the month. Every time you get on the internet, it will use internet and come out of your 200MB you are allowed to use each month.
If your not sure how much internet it will take up, go here to use AT&T's Data Calculator.
If you have WIFI at home or work, you can connect to wifi with your iPhone and use the internet as MUCH AS YOU WANT! It won't count towards your 200MB because the internet is going through your home broadband instead of AT&T's network.
If you don't have WIFI or aren't sure I recomend contacting your internet company. They will tell you if you have wifi and tell you where to get it. If you don't want wifi and you won't go on the internet that much, you don't have to worry about going over data
AT&T data plans for smart phones are required in order to give their customers a better experience with the device. They start at $15 for 200MB of AT&T network data and $25 for 2GB which i guarantee you will not go over of AT&T network data. This data usage does not affect texting, picture messaging, or calling/minutes
Yup,I have a good deal on 1 too. read over all the advice on links first and sixth over on www.iphone-advice.co.cc
Hope you found this as helpful as I did
The data plan gives you access to the internet and to email. All surfing, all downloading, all site checking, all streaming uses data. The data plan covers that use up to either 200mb or 2gb.
It's no different from paying your home internet service provider except that, at home you get unlimited usage and on the iPhone, you're paying for a certain amount of usage.