This article over at JavaWorld tries to explain just what SOA means. It’s still fuzzy. 🙂
What it all boils down to is that it’s a buzzword for integration, and that when you provide services you should provide a separate stable interface to represent them. It doesn’t really matter if that interface is WS, EJB or Corba. What’s new for WS is that all the vendors are jumping on the bandwagon and agreeing on XML and some extra services like transactions and security.
Use integration when you need to. Forget about it the rest of the time. I shiver when I hear someone ask in a planning meeting if we should do SOA…