the really basic stuff can just as easily be learned from the lessons/tutorials that come with the program, they are pretty good. After u get the hang of it check this website

http://www.kirupa.com/developer/mx/index.htm
for some other basic and also advanced tutorials

the newgrounds forums are also pretty helpfull for ppl who are starting out with flash, sometimes even for pro's too
http://www.newgrounds.com/bbs/forum.php?id=2