Freeware Descriptions:
NSIS (Nullsoft Scriptable Install System) is a professional open source system to create Windows installers. It is designed to be as small and flexible as possible and is therefore very suitable for internet distribution.
Here is complete features (taken from authors site):
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.
Features:
- Small overhead size
- Compatible with all major Windows versions
- Unique compression methods
- Script based
- Multiple languages in one installer
- Many features and checks for the target system
- Custom dialogs and interfaces
- Plug-in system
- Support for web installation, file patching
- Project integration, different releases and automatic builds
- Easy and human readable file formats
- Portable Compiler
What’s New in version 2.44:
Major Changes:
- Fixed a bug introduced in 2.43 causing script build issues with some icons (bug #2572035)
Minor Changes:
- Fixed nsDialogs CreateTimer documentation (bug #2595565)
- Global labels didn’t work when declared in unused functions (bug #2593369)

File Size / OS:
- 1.52 MB / Windows 9x - ME - 2000 - NT - XP - 2003 - Vista
Download Nullsoft Install System (NSIS) 2.44: