Christopher Koch has a good article here about SOA and agility here. He is pondering what is really needed from an organisation to get agility out of SOA. The conclusion seems to be that very few organisations has what it takes to make something real out of SOA.
He also mentions that even though people have deployed services, that should give them agility it doesn’t necessarily do that. This brings me back to something I have been thinking about lately; where it seems that many think they can get loose coupling just by implementing a WebService. It gives you some advantages over traditional RMI/EJB etc, but what is really going to kill your agility is the tight data coupling. If the two domains on each side of the service has near 100% overlap you should really start to wonder if you’re doing the right thing by using WebServices.