For Bugzilla you need...
If any of these are already installed just keep an eye on settings that need to be set. Check these with what you used and change them to your needs.
Here we go...
Perl
Verify what perl you are using:
perl -v
It should show something like this:
This is perl, v5.10.1 (*) built for i686-linux-gnu-thread-multi
(with 53 registered patches, see perl -V for more detail)
Natty uses 5.10. If yours is lower than 5.8.1 you need to upgrade it.
MySQL
Verify if you have a MySQL running with
mysql --version
If not installed install mysql-server
mysql-admin
mysql-client 
Make sure to follow guidelines and set up a root account with a decent password. See the links above for how to set up a LAMP server if you need it.
Create a user bugzilla (change it if you want something else)
sudo useradd -d /home/bugzilla -m bugzilla
sudo passwd bugzilla
And create a database and set permissions for user bugzilla
mysql -u root -p
mysql> create database bugzilla;
mysql> grant all privileges on bugzilla.* to bugzilla@localhost;
You need database name, user name and password for the user later on.
Apache
Verify if Apache is installed:
apache2 -v
and
http://localhost
should show a welcome page or a website.
If not installed...install apache2
Configure apache2 as you normally would. See the links at the top for how to set up a LAMP server if you need more.
And now for the important part... setting up bugzilla in apache2:
sudo gedit /etc/apache2/apache2.conf
and edit in the following ...
Alias /bugzilla/ /var/www/bugzilla/
<directory /var/www/bugzilla>
Addhandler cgi-script .cgi .pl
Options +Indexes +ExecCGI +FollowSymLinks
DirectoryIndex index.cgi
AllowOverride Limit
</directory>
(Note the trailing "/" on the first line)
Add a user apache2 if you do not have this already.
sudo useradd -d /home/apache2 -m apache2
sudo passwd apache2
Add the user to apache2 variables...
sudo gedit /etc/apache2/envvars
and include
export APACHE_RUN_USER=apache2
export APACHE_RUN_GROUP=apache2
The cgi addhandler could be in another place if you instal bugzilla from the repositories (see apache cgi how to)
Bugzilla
Install bugzilla3
Or download the latest stable (4.0.2 at the moment) or latest cutting edge version from bugzilla. Short instruction on the latter:
sudo tar -xvf bugzilla-4.0.2.tar
sudo mv /download/bugzilla-4.0.2 /usr/local/
sudo ln -s /usr/local/bugzilla-4.0.2 /var/www/bugzilla
Make sure the directory had rw permissions:
sudo chown -R www-data:www-data /var/www/bugzilla
Perl modules for Bugzilla
Bugzilla uses a script checksetup.pl to check if everything is set up correcly and if things changed to set them up for you. By manually installing the perl modules you can skip this.
Check if all modules are installed
cd /var/www/bugzilla/
sudo ./checksetup.pl --check-modules
If not installed...
sudo perl -MCPAN -e install
localconfig holds the configurations and needs to be set up. So...
sudo gedit localconfig
and change $db_name to the database name, #db_user to the user and $db_password to the password you used during setup of MySQL.
$db_name = 'bugzilla';
$db_user = 'bugzilla';
$db_pass = 'bugzilla@pwpspaswsword';
After saving these settings
cd /var/www/bugzilla/
sudo ./checksetup.pl
will add all kinds of tables to MySQL.
Adding server group apache2 to bugzilla:
sudo gedit /var/www/bugzilla/localconfig
and add
$webservergroup = 'apache2';
To include these changes do a
cd /var/www/bugzilla/
sudo ./checksetup.pl
and this will ask you to setup your administrator for bugzilla.
It works!!
Restart apache2
sudo /etc/init.d/apache2 restart
and open a browser and insert URL
http://localhost/bugzilla/
and I have a working bugzilla login page on my own machine.