If you have any experience building games and coding then it can be a viable platform because you can utilize the majority of your code for multiple devices (android/ios/web/desktop).
If you're inexperienced in building games it's going to be difficult no matter where you start.
Hopefully soon AIR 3.2 will launch and they will suprise us with Stage3D enabled. If so then look into frameworks for actionscript 3 Stage3D. They are geared around making all sorts of 2d and 3d accelerated experiences, especially games. They're much easier than GPU programming.
Consider getting Flash Builder. It's much more preferred as a programming environment to those used to advanced debugging tools. The "Flex" framework is available and integrated directly into the eclipse based IDE so you'll feel a little more familiar with some of the drag & drop components. A lot of gaming / 3d tutorials are written from a Flash Builder standpoint as well.
Actionscript 3 is extremely similar to c-like syntax with a loose typed nature (every variable is dynamically typed, even if you set an explicit type).
Probably the biggest learning curve will be changing frameworks from something like .NET to the built in classes in AS3 for doing the same task. I find everything I do in c#.NET is easier in AS3 in the context for which flash is used.
Jump in here for any questions along your journey and good luck. Note, ActionScript 4 rumors are running about and things like ENUM and strong typing are on the horizon, so it may get a lot more like c#..
I'll stick with flash because i'm doing more than game development, i am also going to have flash cartoons based on my Indie comic in development. you recommend any books or tutorial sites(free or purchasable), on flash game developement, and flash animation?
gotoandlearn.com has some nice video tutorials but to overall get up to speed quickly with flash concepts as well as flash coding in general I would look to something like lynda.com. It's extremely inexpensive video training. It's a lot easier to watch a video (to me) than read a book. There are gobs of videos going over all aspects of the topics of flash itself and flash coding (2 separate things).
Do take advantage of older videos as well though. Learning Flash CS3, 4, 5 is just as useful when you're new, mostly referring to the concepts of flash. The coding you'd want to stay in actionscript 3 land. Avoid learning anything to do with actionscript 2, that's far too old.
There's also a lot of videos on flash builder and flex as well, which is my chosen environment. Learning 4, 4.5 and 4.6 will help you understand Flash Builder, building projects, where to put code, the Flex framework and Adobe AIR. All the way down to creating the actual app itself, and more.
thanks! I'll check these out later
You're welcome and good luck!