There are many new books about Web Services, some of them good. For a good introduction to Web Services, although a bit Java-centric, check out Web Services Essentials (O’Reilly), by Ethan Cerami. For a more .NET-oriented book, look at NET Web Services: Architecture and Implementation by Keith Ballinger (Addison Wesley). If you are developing your projects with Visual Studio .NET, you may want to read some of the later chapters of Building Web Services and .NET Applications, by Lonnie Wall and Andrew Lader (McGraw-Hill).