Generally while working on a project in Flex Builder, when you run your app it generates a debuggable swf and outputs it to the bin-debug folder. Note that this is not the ‘final’ or ‘live’ version that you deploy as your app…it’s bloated with debugging code and such. For that you need to select Project > Export Release Build…, and (by default) it will create a bin-release directory which contains the final output files to deploy the app.