http://members.aol.com/msbritmor/hndstrip.html http://www.zooclub.ru/eng/dogs/uhod/7.shtml
These websites should have good info for you. It's not absolutely necessary, some like the softer coat, but if your dog has a wiry coat and doesn't shed much the dead hairs should be removed using a stripping knife or by hand. I'd assume that the grooming place would use a knife because its faster and causes less stress to a dog that's never been stripped. I use a stripping knife on my toller in the summer to trim her overblown undercoat so she stays cooler. I also think it looks better as she doesn't look so lightly coloured. It completely up to you to decide if you want the coat stripped or not. Any pics of your dog?