I am interested in Behavior Driven Development (BDD)
Are there any good frameworks and/or tooling available for the .Net platform (preferably C# and ASP.Net)?
And when has BDD proved most appropriate to use in real world scenarios? (auxiliary question)
On googling I found Behavior Driven Development (BDD) with SpecFlow and ASP.NET MVC. You might find it useful, take a look. Also go through Behavior-Driven Development with SpecFlow and WatiN
A nice presentation on Pros and Cons of BDD
A channel 9 video Behavior-Driven Development in the Real World
and last but not least an InfoQ article Behavior Driven Development In .NET