What do you want to know?
Lately I've been cranking out PCB's for things it seems like about one every 3 weeks or so, straight to machine assembly. Depending on complexity, the money is in the setup fees and not so much in the actual running of the line. For instance, the solder paste masks can be expensive, but are necessary for running a run. From an assembly standpoint, double-sided is pretty much the same as multi-layer, so it pays to put as much cleverness into the PCB as possible. Also, if you have the ability to create gerbers from source files, often you can export enough data on the board that the people programming the pick-and-place machine can use that to generate the programming for the board assembly.
Having said that, if it's a one-off, or small run, it may be just as cost effective to go to an assembly shop and have them manually pick-and-place the board, however a solder paste mask is usually still required. If you're really adventurous, Sparkfun sells a reflow controller that can be used with a toaster oven for sticking down SMT, but without a solder-paste mask it usually ends up messy enough that it needs cleanup. For the real deal, the amount of solder paste laid down on the board is pretty critical to the cleanliness of the final assembly.
And you can get quality out of China, you just have to pay for it - however at that point unless you're running bazillions, it's often just as cheap to have it done domestically. It's been my experience that you often get odd questions out of the Chinese manufacturers regarding stuff that you have to figure out - they are very risk adverse and will happily make something wrong because that's what you said you wanted it.
There are also companies around that will do both the PCB's and assembly, for prototype runs, for a fee. The trick is following their data requirements, and often chosing from a list of 'stock' components for the jellybean parts.