Start here: http://en.wikipedia.org/wiki/Abstract_factory_pattern
This pattern can be suitable for any kind of service-related technology; it is not specific to WCF, but is more related to the semantics of the services you want provide. So, you need to learn the pattern separately, and the WCF technology separately. Better don't try to find an article or a book which puts these two aspects together. It's way more effective to separate concerns.