In Migrating to Web Services, Roger Costello says: 

How far along is the industry in achieving the Web services vision? Here's my take on it:

• The Web services vision is a mirage at the present. If you jump on it today you will loose.
• The only thing that's real today is XML. Use it.

I agree with this.  My paper on Enabling Web Services is aimed squarely at how to use XML today so that an organization can use web services later.  Roger is more conservative than I am with respect to some of the emerging standards.  For example, he says: "Describe your Web services in an HTML document." where I'm very much in favor of using meta data such as XML Schemas, RDF, WSIL, and WRDL to take a stab at describing these services in a more structured way.  Here's why: they're just not that hard and having the meta data structured gives you much more freedom to automatically process it later.   The HTML will have to thrown away and can be automatically produced from the meta data in any event. 

Roger also has a nice introductory paper on REST on his web site.