WPF is a UI Development technology primarily targeted for Desktop clients. It`s closed rival is windows forms application and it is going to be a dominating UI technology of future. This page summaries some key pointers to learn WPF in easy way 
  1. When to use WPF
    1. When you need very complex UI like IMage control inside Combo Dropdown
    2. When you need Very Rich UI with lots of graphics and animations
  2. Getting Started 
    1. Watch a Simple Demo Videos
      1. How Do I: Build My First WPF Application
    2. Read some overview Tutorials
      1. Introduction to WPF
      2. XAML Overview (WPF)
      3. Dependency Properties Overview
      4. Data Binding Overview
      5. Data Validation:Code Project
    3. Hands On Lab 
      1. Getting Started with WPF
    4. Watch How Do I Videos
      1. http://windowsclient.net/learn/videos_wpf.aspx
  3. WPF Advance 
    1. WPF Patterns 
      1. Model View View Model (MV-VM)
      2. PRISM 
  4. Tools
    1. Visual Studio
    2. Expression Blend (For Advance UI Design)
  5. Recommended Books
    1. Beginners 
      1. WPF 4 Unleashed
    2. Expert 
      1. Programming WPF
    3. Guru 
      1. Applications = Code + Markup: A Guide to the Microsoft Windows Presentation Foundation
  6. Discussion  
    1. Silverlight basics: Validation
    2. Data Validation: IDataErrorInfo Vs INotifyDataErrorInfo
    3. Best WPF Tutorial