How do i add a mesh instance as a child to a gameobject?

Like the title says I wanna add a mesh instance as a child to an empty gameobject.

thanks in advance//The T

A mesh has no transform so instead of adding it as a child I think you could add it as a component:

void AddMesh(Mesh myMesh, GameObject myGameObject){

    myGameObject.AddComponent<MeshFilter>().mesh = myMesh;
}

As for how to dynamically create a mesh please refer to the following link: http://unity3d.com/support/documentation/ScriptReference/Mesh.html