Hi.. I am US citizen and applied for my parents green card in April 2007. I have got the approval notice and for further paperwork I need their birth certificates (they both are born in Goa). The xerox copy of my father's birth record says wrong date and birth record of my mother has wrong name like instead of 'Mira' it says 'Nira'. What is the best option I can use to get it corrected ?

They would have to contact whatever government department that is responsible for issuing birth certificates / id's in India and have them correct it.

You have to REAPPLY for the birth certificates, but I would suggest to send the government more information then yor sent them before ,maybe they confused your family with someone else.