How do I create a pkg from a dmg?

Directly, you can't.

Indirectly, you can use a package creator to create a package from the stuff contained in the dmg.

Here's a google search to help you get started.

XCode also has a utility called PackageMaker.

the same is included in the OS X Server Admin tools , it is a much smaller download - in case the Xcode stuff is not needed.

PackageMaker is very simple to use and self-explaining. You put the files in it, and set where they should go onto the target system. You can customize the installer screens, the text, the license and you can also add scripts that will run before install and after, force a reboot and so on.

Sjazbec wrote:

PackageMaker is very simple to use and self-explaining.

PackageMaker? From Apple? That is one of Apple's worst and most difficult to use developer tools.

After searching around macupdate.com a little here some more possible candidate pkg creators:

Iceberg

Packages

InstallPKG

Composer

I am making a custom download for PackageMaker... I will give you the link soon...