Now I are back from work.... :-D
Youre right regarding AS. Its fairly easy to pickup, and flash does have a pretty good inbuilt help to go through all the functions. Also helpful stuff like gotoAndPlay(framenumber), can easily be recalled by pressing <escape> g p. Most of the mainly used functions have these shortcuts which makes it nice and easy!
The main problem with some books is that the basic stuff of learning how to draw lines, the fact that once you draw something, you generally have to make it into an object to start manipulating it, and that moving stuff around is called tweening, is fairly simple to pick up, but I've seen some books which draw on this an awful lot. Ive had a poke around in waterstones occasionally when im in town, but all the books I see are covering these basics, which to be honest aren't that hard to pick up, or even find tutorials on google for. Its usually a fair chunk into the book before I start finding vaguely helpful stuff, and even then , its still covering things that can easily be googleable.
Best bet is to start playing around with makeshift scenarios, and working out how to do it. Learning by experience, and having your own goal in mind, rather than reading a book/looking through one of its tutorials, i feel is a better way to get to grips to it.
The chances are , that whilst searching through websites looking for answers on how to do certain things, youll come across other interesting things to try/learn and you can easily go off on tangents and learn those bits too.
Learning flash>html/js interaction is handy (in flash: "getURL('javascript:myjsFunction();');", and in the html page containing the flash swf, you can have the "function myjsFunction(){ alert("ARGH"); }" and huzzah you can talk between them), as well as learning how to manipulate XML (which again, is fairly standard xml scripting calls, which I am assuming that you know from AJAX stuff).