Nullsoft Scriptable Install System is the best open source program packager.

NSIS (Nullsoft Scriptable Install System) is a professional open source system to create Windows installers. It is a simple elegant yet powerful solution. It is designed to be as small and flexible as possible and is therefore very suitable for internet distribution.

Download NSIS from SourceForge

You have created a small software or applications, using a more traditional high level language language (Java, C++, C##, Basic etc), and you want an installer program to put it in program files and create registry entries..etc.Here is the best open source packager that saves you $500 to $2000 of commercially available packagers. NSIS provides faster, clean installer and uninstaller.

I have created several sample packing programs, using HM NIS Edit & NSIS, for my applications such as lightsql, rssflash, credit card validations

I used the HM NIS Edit tool to build my first NSIS installer. The wizard took me through the basic steps of creating my first installer, and it wrote the code I needed to get started. The code was a little weird at first but I’m a programmer so I got the hang of it eventually. I was able to do EVERYTHING I wanted with NSIS. I’m using it on a fairly large scale and I’ve had absolutely no complaints with flaky behavior from thousands of users now. On top of that, the final executable NSIS produces is much smaller than other packagers. And an NSIS installer performs the installation MUCH faster than other packagers as well.

So for me it was a no brainer. Once I got over the initial learning curve of NSIS I never looked back. I highly recommend it for any programmer who wants to build good Windows Installer packages for their software.

Being a user’s first experience with your product, a stable and reliable installer is an important component of succesful software. With NSIS you can create such installers that are capable of doing everything that is needed to setup your software.

NSIS is script-based and allows you to create the logic to handle even the most complex installation tasks. Many plug-ins and scripts are already available: you can create web installers, communicate with Windows and other software components, install or update shared components and more.

Awesome product, stable and FREE, great work Open Source!