Links to Windows Phone 7 Design Tutorials
• Metro Design Language of Windows Phone 7
• Windows Phone 7: Starting to Design an Application
• Design Tips and Tricks for Windows Phone 7
• Layout Tips and Tricks of Windows Phone 7
• Taking Advantage of Photoshop Templates
• FXG Import and Workflow
• Designing for Gestures on Windows Phone 7
Via MSDN Blogs.
You may also want to check out: Windows Phone 7 Tutorial Series : How to build & deploy WP7 applications | The Windows Club