if you know how to build procedures and you want to know how to build applications ... that kind stuff. do a search for "architecture made simple" @psdn.com. theres a whole series of papers, code samples, webcasts etc.
i'd recommend starting there most other oera papers are either waaaaay too vague or too detailed to get started with (avoid anything with john sadd in the title).
one thing, big one, it doesn't cover (if i remember) is that it doesn't talk about what services you'd typically build, expose. other then services are coarse grained or something.
some have said that it may be more on the academic side and less suitable to the real world. not everything fits together and it still has some unsolved questions.
take it as a reference, another point of view, if you will. if you feel some parts don't add up or only complicate, throw it away and only take the things you like.