saved audio files are compiled together...so you would have to "decompile" the audio file to edit it again...there are some software to do it, but i'm not completely sure what apps are out there for that...maybe check versiontracker.com to find some.
as for other apps, again, they are compiled and you would have to decompile them. first, you need to know what programming language that was used to program the app, and you would have to find some decompilers that could handle that language correctly (also, different compilers have special instructions and usually you have to decompile the app with the one that it was compiled with to decompile correctly).
hope that helps.