L.A.
I had some friend's who had their names changed as teenagers b/c the new step dad adopted them.
My other friend however kept his father's name and hyphenated it with the new step-dad's name. They actaully sounded really nice together.
I would think this to be a lengthy process and it would take some serious contemplation on if it is really the right thing for the child, especially if the birth father is still invoolved in the child's life. For some situations it is, for others, it seems to be just another vindictive way to use the children against the dad.