Please respect the plattform habbits: Installers are common on Windows. I suggest to use WIX for windows installer because the output is a proper msi-file installer. Other people, including Nokia Qt Development Frameworks use the Nullsoft Install System. On linux, you usually not have installers but packages for the package manager of the linux distribution. You do not make friends when you present a windows-style-installer on linux. You can offer one but you have to offer binary packages for linux distributions to not piss people off that like the linux package managers.

For the mac, there is an install builder by apple but usually you either put the .app in a compressed disk image file or zip the .app.