Packages is an Integrated Packaging Environment. It lets you easily create simple package projects and manage complex distribution projects.

Packages can produce installation packages or installation distributions for Mac OS X 10.5 or later. Both types are supported by Installer.

Package lets you customize the build settings of your projects and the settings of packages so that things are built where and the way you want them to be.

Packages lets you define the payload of your packages through a familiar user interface. You can check and change the properties of the items in the payload.

Packages can manage the most complex hierarchies of installation choices. It lets you define from the simplest to the most complex requirements.

Packages lets you customize the title, background, welcome message, read me message, end-user license agreement and conclusion message of distributions. You can include multiple localizations and your own installer plug-ins.

Packages' projects can be built either through the application or through the command line.

You can find additional information in Apple's document Software Distribution (Document is currently MIA on Apple Developer web site).

If you have general questions regarding Apple's Installer application, you can try the installer-dev mailing-list.