From Cyclone3 Wiki
What is Cyclone3?
Cyclone3 is extremely flexible and mature open source framework (and CMS) designed to develop content management systems, custom intranet applications, command line and GUI applications. Cyclone3 was originally a proprietary framework used for commercial purposes for almost 8 years. Read more on Cyclone3, projects powered by Cyclone3, companies using Cyclone3 or Cyclone3 documentation.
How to start with Cyclone3?
If you decide to give Cyclone3 a try please read how to install Cyclone3 Framework. After Installation you will probably want to read our guide on how to setup and create new domain service which is in most cases a web page. You can also check out a list of framework, administration and standards-related infos.
If you are a coder, you probably have Cyclone3 Framework already installed and need to create new modules or customize the existing ones to your needs. You can check the creating a module page to find out how. Also check out the development-related pages list.
If you are a webdesigner, you want to look at creating a webpage tutorial for webdesigners.
If you want to install the Firefox addon to start working, visit www.xul-cms.com and click Install to get the latest release. If you're new to Cyclone3 XUL CMS, you can check out other content on the page, to find out how the interface looks and how much you can do with it.