If you want to distribute files, either from a CD or across the Internet, they need to be provided in a format that can easily be handled by all users, from advanced through to beginner level. For instance, many new users may not know what to do when presented with a ZIP archive. Although the facility to unarchive a ZIP file is embedded within Windows and Mac OS X, how does the end-user know where to put the files within the ZIP?
Another option is to produce a self-extracting ZIP archive that prompts the end-user for a destination. Still not the ideal solution as the end-user needs to know where they should store the program files. If you’re a freeware developer, you also need to purchase a commercial application to produce a self-extracting ZIP archive.
NSIS (Nullsoft Scriptable Install System) is a tool that is aimed at freeware and other developers who want to create their own installer, whether it is a simple installer to copy files to a particular location or more of an advanced installer that will enable the end-user to configure their setup.
NSIS is completely free, supports a range of compression routines and will produce an installer that will work on any Windows machine from 98SE through to Vista. It will also support web downloads, so the end-user can update their files through the installation routine, amongst many other features.
Note that this is the portable version of NSIS.