We live in Georgia and have a 17 yr old son who had a baby with his 19 yr old girlfriend he signed the birth certificate but we are trying to find out if that legitimizes the child or if we need to go through the courts he still lives with us and is still in school so we will be the ones financing anything that has to be done and are on a fixed income so we need to do this as cheaply as possible and as soon as possible because we forsee problems very soon.

If he is on the birth certificate there is nothing more he needs to do, except file for visitation and set up child support though the courts.

This is not correct if he sign the birth certificate that means nothing except to guarantee that the baby will have his last name you need to petition the courts or get an attorney.There are legal aid and attorneys that have to do a few pro bono cases a yr. Google and see what is available to you and your state. I know because I am where you are.

He is on the birth certificate there is nothing more he needs to do, except file for visitation and set up child support though the courts

http://www.ehow.com/how_6847918_legitimize-rights-child-custody.html