Possible Duplicate:
Monitor wifi usage?
Is there a way to have an alarm warn me every time I spent another 100MB and telling me the total I've spent on the last billing period to avoid going over my limit and into debt in Android?
Topic data-monitoring android
Category Android
I'm using Network Monitor. With this free app you can track 2G/3G and WiFi traffic as separate stats. Also you can set up warning message for each stat.
It looks like NetCounter will do what you need
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