I will be travelling to India for couple of weeks and would like to use my iphone 4 with a prepaid service. I believe airtel or vodafone provides micro-sim. Is that information correct? Any others? Also, it seems like they both have pretty much similar priced prepaid plans. Who has better coverage and better 3G speeds with iphone 4 (ATT & unlocked)? I will be using it mainly in Mumbai and Bangalore. Thanks in advance for any help.