I think what happens is you get in touch with them and people who work there come round to your house and assess the suitablity of your house and yourself. If they like what they see then they wil offer you a puppy or the let you take the one you want. I'm not sure if there is a cost involved for the rescue centre or not, but you may have to get the dog chipped and have it's jabs at the vets. I think the adoption process will be explain on the two links in my last post
Another note to add is that if you take one of the puppies from a rescue centre, they will make you agree to hand it back to them if you cannot look after it, for any reason at any point in the future. This stops people adopting puppies and selling them on.