Alex Knight explains how with the introduction of Expression Blend 3 comes the ability to import Photoshop files directly into your project, allowing you to create designs in a product you are familiar with and not have to start from scratch when applying it to your Silverlight or WPF application.
Expression Design has always had the ability to import Illustrator files. By allowing you to now import both Illustrator and Photoshop files directly into your blend project, Microsoft has supplied the tools to fast track your designs from concept to working application.