You could start with Adobe TV. There is a lot of videos about Flash and Actionscript 3 tutorials.
I also suscribe to Lynda.com, the online training library. A lot of tutorials on Flash and Actionscript with excercice files. Great !
I go at goToAndLearn.com. Lee Brimelow, an Adobe Evangelist, post some free tutorials and he is a great trainer ! I love his tutorials !
These are my favorites ...
Hope this help !