The main link is part of O'Reilly Publsihing's ever-widening archipelego of XML sites - many of the articles are not related to web service design patterns per se. Sometimes one gets the impression that the real purpose of design patterns is to sell books about design patterns, but they are very useful nevertheless.
Note: this article first appeared as "An Intro to Service Oriented Architecture". The new "Intro to SOA" focuses primarly on the OASIS SOA Reference Architecture, which seems to be the most mature and complete of the SOA standards to date.
The Wikiopedia defines Service Oriented Architecture as: