Planting, establishment and formative pruning of ornamental and fruit trees
For an excellent planting guide go to http://www.thornhayes-nursery.co.uk/advice_planting.php
Also on the Thornhayes Nursery web site you will find useful notes on choosing and planting fruit trees.
There is also a very good list of trees and their resistance to Honey Fungus. Unfortunately, malus are in the very prone category,