The latest release is packaged as deb packages and is available via a PPA for recent versions of Ubuntu:
sudo add-apt-repository ppa:yaybu-team/stable sudo apt-get update sudo apt-get install python-yaybu
A .dmg is available from the releases page at GitHub.
Drag the Yaybu icon into your Applications folder. When you first run Yaybu it will prompt you to install command line tools. This will simply create a symlink from /usr/local/bin/yaybu to command line tools embedded inside the Yaybu bundle.
You can drop Yaybufile files onto the Yaybu dock icon to automatically start a Yaybu shell for a project.
An unstable ‘nightly’ PPA is available for lucid and precise. You can use it like this:
sudo add-apt-repository ppa:yaybu-team/nightly sudo apt-get update sudo apt-get install python-yaybu