I have just discovered that I can use my iphone's 3G internet on my ipad using a 'personal hotspot,' however when I connect it warns me that extra charges may apply. Can anyone knows about this sort of stuff tell me what these charges are for. Or if its limited to if I go over my monthly data limit on my phone contract?
Thanks
Thanks

I got a fairly simple phone from AT&T over the summer as I was in the states for a month and I decided it would be useful when staying with my family over there which I do fairly occasionally.