I know the different ways of making PCBs at home, but I can't seem to find a lot of information on how board houses professionally make their PCBs. Is this how they do it?: http://www.youtube.com/watch?v=8-WGaAmpfOU&feature=related
You might want to read/watch this tour of Advanced Circuits PCB Manufacturer which was posted to Hack-A-Day in June last year. I think you'll learn a great deal. The scope of your question is way too broad to try and address directly on this site.