I kinda answered my previous question about data annotations. I have discovered the wonderful world of Fluent API.
I am wondering how this works when you have view model classes though - I am using view model classes in my application and copying the results of posts into model classes that are tracked by EF. How do I tie the data validation performed by Fluent API to my view model classes?
You can't do it with Fluent API. Fluent API is used for mapping relations between objects. Try to search web for Fluent Validation.