I recently published a new screencast on Channel 9 on transitioning to Windows 7. It is available at https://channel9.msdn.com/Events/Windows-Development-Boot-Camp/Windows-7-Development-Boot-Camp/Windows7ApplicationCompatibility1.
Here is the official abstract:
So your company is upgrading to Windows 7, and you're a bit nervous. You will have to fix any applications that stop working when the OS is upgraded. Don't worry - in this session, we will discuss the top compatibility issues when transitioning from both Windows XP and from Windows Vista to Windows 7. For each issue, we will explain the problem, how to debug it, and how to fix it. You will walk away understanding the major differences in the latest version of Windows.