Last night I watched an MSDN Webcast, called Refactoring For Your Code Base (Level 300). Brian Button was the presenter, and let me say that he did an excellent job presenting the material. The presentation was a very nice balance of slides and refactorings demonstrated in Visual Studio. The demonstrations were very easy to follow and the webcast is a fantastic introduction to refactoring.
His first demonstration showed the “Rename” and “Extract Method” refactorings. Briefly, he demonstrated how a tool like JetBrains ReSharper could help you with such refactorings. However, Brian wasn't pushing or recommending any tools, he just wanted to introduce the fact that there are tools available and that Visual Studio 2005 would also have some refactoring capabilities as well. Nicely done, Brian, as I would have recommended that all C# developers run, not walk, and buy ReSharper. You're a better man!
His other demonstrations showed a number of other refactorings, like “Extract Superclass”, “Pull Up Constructor Body”, “Pull Up Field”, etc. Again, it was really easy to follow the refactorings and they were all done by hand to show the refactoring process and not demonstrate a tool.
As you would expect, refactoring was done in very small steps and Brian had a set of unit tests pre-written to demonstrate the importance of unit tests when refactoring. Brian didn't dive into the tests and how to create them, which in my opinion was a smart move. He just reinforced from time-to-time the value of the unit tests as a safety net when doing the refactorings. He also ran the unit tests after every small change / refactoring which supported his words, yet was not a distraction during the webcast.
He recommended a few books for additional reading:
He also recommended the Refactoring.com website, which is basically the main place to go for refactoring information.
If you are looking for a great introduction to refactoring, I highly recommend the webcast.