First of all welcome to India,
I will answer you pointwise,
1. Yes 3G is available in all metros & most smaller towns, and EDGE is available everywhere else. (for iPhone please wait for the real users to leave a comment here)
2. Yes, in villages perhaps the situation could be even worse with only GPRS (GSM) access or no internet, but right now Indian telecommmunication has achieved covering around 80% of population areas.
3. Internet cafes are available in smaller cities, but not sure all of them
know about WIFIs.
4. No, i guess you may have to go out to access internet or ask them if they have the arrangements within their compounds. (thats for smaller towns)
5. No, I am sorry 24x7 is not there for internet cafes in smaller towns, but in metros the situation is not only stable but excellent.
6. Take BSNL 3G sim card when you come to India, they are Govt. Enterprise and so their infrastructure is better. You should also add AIRTEL to this list because of its stablilty and coverage plus points.
I guess i had been honest in reciprocating.
welcome again!
