Ichthux is an additional package in the Ubuntu repositories, so, as such, there are no downloads available.
Procedure to install Ichthux

1. Download Kubuntu
2. Install Kubuntu on your computer, in your preferred configuration
3. Open your software management tool (KPackageKit in 9.04 and above, Adept Package Manager in 8.10 and lower) and do a search for "ichthux-desktop"
4. Install this package.
5. Logout and log back in to your new Ichthux desktop!