Automator-generated apps - Backwards compatibility
I don't know how backward-compatible they are, but you can also save scripts as applications from AppleScript Editor.

Another option might be to use Platypus.


  Platypus is a developer tool for the Mac OS X operating system. It creates native Mac OS X applications from interpreted scripts such as shell scripts or Perl, Ruby and Python programs. This is done by wrapping the script in an application bundle along with a native executable binary that runs the script.