My 4 month old currently has his fathers last name, I want it changed to mine. WHat do I need to do?

A name change must be filed in the Probate Court of the county that your child resides.  They usually have the application that you will need to complete to get that in process in motion.  A hearing will then be scheduled to present your case to show that a name change is in that child's best interest.  If the child's father consents, a full hearing may not be necessary.  Additionally, there are factors, that if proven, you can have the name changed without his consent.