Possible duplicate:How do you decompile a SWF file
Does anyone know if there is such a tool?
Sothink decompiler is a good place to run
try Sothink SWF Decompiler , I used it once and its nice
You can even try the Flash Decompiler Trillix
Sothink decompiler is good.But you have to work hard to understand decompiled source code.