Download this book: SOA in Practice
great book, I love this.
SOA is Service of Architecture. Some people said it will replace ERP soon.
briefly speaking , is about architecture of software
XML , web service is more popular.
and the way we exchange information is changing.
I think in the near future, the SOA is main term when we talk about how to build a software.
hope in my thesis , I will have opportunity to apply it in practice not just in theory.
The key is flexibility.