Creating installation documentation is always a complete nightmare. In the past I've used various editors such as HtmlHelp and FastHelp to generate pretty CHM style help files for appliations. In the last few years I've come to see how valueable a wiki can be for this. Instead of spending hours creating documentation you can let your users who are passionate about your product assist in this documentation by using a wiki.
I have stood up a rudimentary wiki for my MP3-CMS music server project.