A colleague of mine recommended the book "How To Talk To Customers" by Diane Berenbaum and Tom Larkin. I found it very informative and plan on implementing the recommendations as my new service desk staff is built over the next few months. I have also started recommending the book to the other IT Managers at our company in hopes it will spread and we can all provide a better level of service.
The book is very much MT style with actionable things you can do to be more effective right away. It's full of (good and bad) examples. While it is ideally suited for an inbound or outbound call center, it has applications in just about every customer facing organization (ex: sales).
The core of the book is built on the concept of "MAGIC" (Make A Great Impression on the Customer.) The acronym also stands for the basic steps of moving through the process. Everything from how you answer your call, to closing the conversation is covered. These behaviors make up the 33 points of MAGIC. My colleague uses these 33 points to measure her employees. From the interview process to performance reviews, these behaviors are a foundation for her successful service desk - a practice I intend to emulate.
The book is a quick read and very easy to relate to. If you interact with your customers, be they internal or external, I highly recommend you read "How To Talk To Customers."