A one of the major improvement in SSIS 2012 is the Project Deployment Model. The project deployment file is a self-contained unit of deployment (.ispac extension) that includes only the essential information about the packages and parameters in the project.
In this new version, the concept of Parameters has been introduced to assign values to package properties similar to Configurations in earlier versions.
Also a project, containing packages and parameters, is deployed to the SSISDB catalog on an instance of SQL Server where in the earlier version we were able to deploy in both file system and SQL Server (MSDB).
Along with several other new features, another notable enhancement is shared connections across a package which is really a good feature with a reusability perspective.
If you already have packages with earlier versions so no worry :), you can still execute them in SQL Server 2012.
You can also upgrade the package by Integration Services Project Conversion Wizard from Visual Studio or SSIS Package Upgrade Wizard from SQL Server Management Studio (SSMS).
Appreciate your comments/suggestions for the post.