O’Reilly is running an article by Colin Moock titled What is a Flash Component? It is a very good introduction to Flash MX components with plenty of links to other relevant resources.
Of course, Colin is the author of ActionScript for Flash MX : The Definitive Guide, so you know that the article is worth looking at.

Kudos to Colin! A well written article that gives a good high-level overview of ‘components’ and provides numerous links for more detailed info.
thanks
A great resource, thanks
Nice job, keep up the good work.
I tested the code, very useful, thanks
muy interesante el tema
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