There are a couple of great Apple Packaging applications out there that have functionalities including snapshot and fseventsd monitoring as well as integration with popular application deployment suites, but there are very few, if any, that allow for easy code review, consistency, and portability.
Enter The Luggage.
Joe Block has created an open source tool that will allow you to create packages based on GNU make that he calls The Luggage. With The Luggage, package definitions are clearly spelled out in plaintext files, can be shared and stored in version control systems, and can be replicated by peers with ease.
Since GNU make can be daunting at first, I've written an article on creating packages with make and The Luggage. As we all move towards modular imaging techniques (InstaDMG, System Image Utility), it's becoming more important to have all our applications, scripts, and customizations in package format. It's my hope that The Luggage will make this process much easier for you.