Last year I had to give a powepoint presentation on Web Services. I noticed some good books at barnes and noble that discussed the subject. These books were specific to Java and discussed Web Services in a very clear fashion. They gave some elementary examples that were easy to understand.
I have not yet had the pleasure of creatin .NET Web Services. From what I have read, Visual Studio creates all of the necessary files for you, and shields you from having to sink yourself into WSDL, SOAP, UDDI etc.
I say go to your local bookstore and look at some books. I did not use the book in question at the time, because of limited financial resources available at the time.