The recommended installation method is to clone the GitHub repository :
$ git clone git://github.com/cykod/Webiva.git
This will allow you to track the changes which will be coming fast and furious until the 1.0 release.
If you want to download a static copy, you can download the tarball of the latest release (0.9) at:
http://github.com/cykod/Webiva/downloads
Please see the installation instructions in INSTALL for more details on how to get the system up and running and consult the installation instructions at Webiva.net/doc/user/installing for the latest updates and platforms.