Drive amalfi doesn't have a website.. his name is Salvatore and I will get you his email address. I have never used him but hear good things about him. There is a company we did hire:
Http://www.seesorrento.com
Marcello is the owner. He gave a great tour. Never shuts up.. Really loves his country. HAd fabulous tour of Amalfi coast.
Both of these guys pick you up at the ship. If you are told to taxi into town that is the wrong company to hire- too much of a hassle.