Is there a concept of after life in Buddhism? I know that Nirvana is not like heaven the one they have in Christianity and Islam, but rather just a state of mind in the present world. Then what happens to someone who dies after becoming the enlightened one or becoming a Buddha? Where does he/she go?
There are 2 types of Nibbana which are:


sopadhishesa-nirvana (nibbana with a remainder) - while alive 
parinirvana or anupadhishesa-nirvana (nibbana without remainder, or final nirvana) - after death 


Nibbana is being blown out. So once you die for a person who has attained Nibbana does not go any where. The person is extinguished. This is like when you blow out the candle the flame does not go any where. The conditions for combustion are not there hence it extinguishers. This is similar to Nirvana. Conditions for future rebirths are no longer present hence you get extinguished.