I can highly recommend Deke McClellands tutorials at Lynda.com. I don't think there is a specific set of tutorials devoted to composting but the tuts on the subject are extensively included in his advanced series. He goes into it in quite detail, using different methods and techniques. Use the search feature to find the pertinent tutorials.
I have not checked out what is available for CS5 but I understand that the material has been updated for this release.
I have found that Topaz Remask is very useful and takes the place of some of the more complex methods. I have tried most of the other masking programs but this seems best. There are little tricks you have to pick up but once you do it is very powerful so don't give up on initial impressions. They have a series of video tutorials that are are helpful but make it seem too easy and fast, it never is but that is advertising.
I usually use a combination of Topaz and conventional methods. On trick with Topaz is to run the plug in on a copy layer with a blank mask attached. This will result in getting a mask for the extraction instead of a pixel cutout. Using the mask allows much more flexibility. For example, if a I get a good extraction using Topaz except for a certain area, I can work on the problem area with an independent mask using any tools which are appropriate. When I get the problem area mask good I can combine it with the Topaz mask using Apply image (covered by Deke).
The Refine edge tool in CS5 is also very good but it too requires learning the tricks. I use it with the above methods.
I have not done much works with hair extraction lately, working mostly with landscapes with latticed tree areas in the sky. The techniques are the same for both. Keep in mind that there are some images which will never extract well if they contain low contrast, same colored areas blending into the foreground and back ground. Subjects shot for extraction where the background is controlled in camera (green screen not needed), extract quickly and accurately. Also the tone of the image background should be close to the composted background. If you try putting a subject shot on a bright white background onto a very dark background, you are asking for problems and a lot of work. Blending modes are sometimes very useful. I recently composted a wine glass full of wine against a close up of some grapes. By selecting the correct blending mode I was able to bring out the transparency of the wine glass showing the grapes behind. See attached which is a little contrasty and saturated as it is from a a softproof for printing.
Rereading you initial inquiry, I see that you are interested in architectural extractions. I assume you are interested in masking the windows views - a properly exposed exterior view over the blown interior window views. In many cases, the simpler methods work satisfactorily and faster, especially for web work (ie real estate listings). I still suggest learning the advanced methods even though in most cases you won't need them. There will come a time when you have a large translucent floral arrangement against a window (that is, complex subject) and the client wants a high rez result. You should be able to handle it.
Larry
