Does anyone know how i can check how much of my 2gb monthly data i've used??

I just went over my 2gb data allowance getting the " you are not subscribed to a cellular data service " so i have to wait till my bill is payed again. is there any way i can find out how much i've been using so i know for next time not to go over it??

btw ; I have a iphone 3gs and my carrier is AT&T And Network is H2O

Go into Itunes, select the iTunes store and type in data meter

There are loads so pick the one you think will be best

If you go into your Settings and scroll down to "Phone", then select "AT&T Services", it gives you a list of options to check your bill balance, data usage, etc. Just click on the one for data and they will send you a text message in about 30-60 seconds with how much data you've used and how much is left and when your billing cycle ends. It also shows what #s and symbols to dial if you prefer to access it next time from Phone instead of going into Settings.

When i try to use the at&t services i either get a error message or the text tells me that this isn't for my account type which i dont understand..

Try calling #3282. When I do this I get a text with data and text usage. I have Verizon so I'm not if it's only a Verizon thing.

For AT&T you dial *3282#

Almost every carrier on earth makes an APP that calculates this for you. Search the app store for the name of your carrier.