Macintosh Package
From Director Online Wiki
Nothing much here yet, but you could do worse than look at the following links:
Macromedia's page about bundles Apple's introduction to bundles
If you like to learn by example, you can create a simple applescript and save as an application bundle. This won't create the OS9 side, though. Right click or control click on the resulting app and choose show package contents. Here's a line of applscript that can be used:
display dialog "Hello world." buttons {"Ok"} giving up after 4 default button 1
TIP: Create the application alias for the OS9 side of the package (or bundle) on the disk image to be burned.