Hello fellow member... Are you looking for a book in English only? Because in French i can recommend the Marabout book "Petits plats comme au Vietnam" from Orathay, who is a contributor to several magazines that i have. The recipes are very simple and well explained.
I have a Vietnamese book too in English called Recipes from a Vietnamese Kitchen which i love and actually member indexed, but i think it is less simple than the other one.
Otherwise a very well explained blog i like is vickypham.com, with step by step photographs etc.
I hope that helps! Agnes