- Package - Collection of setup files for a specific application
- Program - Defined for a package which is a command on how to use the files in the package to actually perform the installation. One package could have multiple programs defined, such as a silent install option, a user interaction option etc
- Collection - A set of computers (or users) that are grouped together
- Advertisement - Offering a program to a specific collection. Essentially installing the application to a group of machines
These concepts still exist in Configuration Manager 2012; however, packages and programs are no longer the primary method to deliver applications to users.
With the new application model, a single application, such as Office 2010, can have many different deployment types-- such as setup.exe installation, execution with App-V or deployment to a mobile device. The right deployment type is used depending on the machine the user is currently using.
If you want to take existing packages and programs to Configuration Manager 2012 and use them with the new application model download the Package Conversion Manager (PCM), documented at the Microsoft site. You might also be interested in "10Steps to Migration: Configuration Manager 2012."