I have posted a series of blogs on extensibility support in Coded UI Test.
- Introduction to Coded UI Test Extensibility
- “Hello, World” Extension for Coded UI Test
- Introducing Sample Excel Extension
- Technology Adapter of Sample Excel Extension
- Property Provider of Sample Excel Extension
- Action Filters of Sample Excel Extension
These should get anyone looking for writing extension for Coded UI Test, get started. Use the Coded UI Test forum for questions\more info.