Wife's Oath on April 1st, She is Changing Last Name, But How Can we change Kid's Names?

[Diamonds]

Hi,
My wife passed the Interview on March 3rd, 2010 and got the Oath Letter sameday, She is Changing her last Name.I want to Apply US Passport for my wife and 3kids.But I want to change the Names for all three Kids.So what is the procedure? We have to change the Names Before Applying the US Passports or Can we change the Names when my wife take Oath?(Oath time)

1. Is it possible for my children too, because my wife also changing the last Name.
2. Do we legaly need to apply N600 for my children or the US Passport is enough with Passport Card? 3.
4. How much cost to apply Us PassPassport and the Passport Card ?
5. What Kinds of Docs we need for aplying Us Passport for my kids?
6. Can we apply Kid's Passport at the same time when I apply my wife's Us Passport?
7. What Documents do we need for the Kids?
8. Do we need to Inform Indian Embassy when we become Us Citizen or Just Apply for the Indian Parmanet visa Card? There is not Dual Citizenship allowed with
India right?
9. To Apply Us Passport Both Mother-Father should be US Citizen or just any one is ok?

JonyCash,BobSmith,Vorpal and all you guys Plese advise me.