XSANDER  SWF to FLA converter is one of the best products I ever try. It’s truly indispensable and very helpful utility which gives an opportunity to convert SWF to FLA and easily modify Flash movies without initial source code. This converter already saves a lot of my time and help me to learn how other’s flash works. SWF to FLA converter is much better than other similar utilities and have truthfully user friendly interface. It is the only SWF to FLA Converter for Mac OS that I was able to find working and stable...!

If you don’t believe me just download and try it yourself.   
(Version 1.1)