With Ubuntu 8.04 you can ``apt-get install ganglia-monitor gmetad php5-gd'' to collect statistics on your machine; the stats will be stored in rrd files under /var/lib/ganglia/rrds. Unfortunately, the package named ganglia-webfrontend that is needed to graph these rrd files through your webserver is unavailable.
The solution is to install an older rpm, back from ganglia 3.0.3 known as ganglia-web-3.0.3-1.noarch.rpm. Grab it from the ganglia.sourceforge.net project page. The reason for going back to this release of the webfrontend is that the more modern ones have an unmet dependency for php-gd, which in turn depends on many more rpms.
rpm --install ganglia-web-3.0.3-1.noarch.rpm
Once installed, you configure your webserver to serve up the php files from /var/www/html/ganglia. Use index.php as your entry point.
Also advisable is to set an explicit 'authority' line in your /etc/gmetad.conf: for example, authority http://localhost/ganglia/index.php pointing back to your entry point.