I'll cut straight to the chase, I definitely recommend SOA Patterns to anyone interested in SOA.
Even though its currently only available in MEAP, and is a bit rough and ready, and isn't complete, it's still great stuff and well worth your time.
Now I've said that I'll give a quick run through. Essentially the author, Arnon Rotem-Gal-Oz, has decided to focus on the practical aspects of SOA and in particular with a focus on the software architecture aspects of SOA. It thus doesn't cover the business aspects of SOA, which is fine with me as those topics are covered elsewhere.
With that tight focus in mind Arnon has already managed to pack in a range of very interesting and valuable patterns. Each pattern includes the problem, solution, technology mapping and quality attributes. There is already the feeling of a pattern language about it which I think will evolve as later chapters are added, this should allow you to describe a complex system with just a few high level patterns or to dig into more detail by discussing the lower level patterns they compose.
In addition Jan has posted a review of the book.