On mssqltips.com you can find my latest post Parallel execution of child SQL Server Integration Services Packages using For Loop Containers.
The post describes a very simple way how to parallelize execution of child packages in SSIS. There exists third party components for parallel execution, but sometimes they are costly and some time they do not work exactly as expected. The for loop containers allow us to implement it using purely using the building components and at no costs with exactly defined behavior.