NSIS (Nullsoft Scriptable Install System) is a professional open-source tool for the development of Windows installers. It is designed to be as small and flexible as possible and is therefore highly suitable for internet distribution.
NSIS 3.0b1 is released with lots of build fixes, revival of nightly builds, automatic execution of our test suite along with the nightly build to make sure releases are always up to snuff, and lots of patches from our loyal users.
Download:
http://nsis.sourceforge.net/Download
Release notes: