I've spent too much time in book stores looking for good books on software design (including SOA and web services design). Yet the one book that I find myself most frequently referencing has been on my bookshelf for years, it is:
"The Practical Guide to Structured Systems Design"
The first thing you'll note is that the book was published in 1988.
The second thing that you'll note is that the book never mentions web services, service oriented architectures, XML, etc.
What you will find is some clear, actionable information on modular design, cohesion, coupling and design strategies. Is it a bit dated? Sure - but many developers are designing modular services for the first time. The book clearly explains data coupling, stamp coupling, control coupling, common coupling and content coupling. Well done!