Nobuyuki Akama has started a series of articles that give a very good introduction to WCF. The first two articles in the series have been posted so far. I like how detailed the examples and explanations are. You usually don't see that level of detail in introductory material. I think that you shouldn't have to wait for the advanced material before seeing how the system works and seeing exactly what happens on the network.
Hello World, WCF !!
- Part 1. WCF に導入されている新たな設計概念
Part 2. Hello World WCF サーバの開発
- Part 3. Hello World WCF クライアントの開発
- Part 4. IIS ホストの使い方
The current articles give some background about WCF and provide the server half of the sample application. The upcoming articles provide the client half of the sample application and talk about the hosting and activation of services.