Updated Ubuntu installation instructions. Thanks to diablorick.

INSTALL_UBUNTU_8.04.txt

+Installation
+-----------
+
+It is recommended to use a clean (fresh) Ubuntu 7.10 (Gutsy Gibbon) install where you selected no additional packages or servers during setup. Then follow the steps below to setup your server with ISPConfig 3:
+
+Now become root user by executing:
+
+sudo su
+
+and entering the password of the user that you created during setup.
+
+Edit the file /etc/apt/sources.list and comment out the line beginning with "deb cdrom:....", then run:
+
+apt-get update
+apt-get -u upgrade
+
+
+1) Install Postfix, Courier, Saslauthd, MySQL, phpMyAdmin with the following command line (on one line!):
+
+apt-get install postfix postfix-mysql postfix-doc mysql-client mysql-server courier-authdaemon courier-authlib-mysql courier-pop courier-pop-ssl courier-imap courier-imap-ssl postfix-tls libsasl2-2 libsasl2-modules libsasl2-modules-sql sasl2-bin libpam-mysql openssl courier-maildrop getmail4
+
+Answer the questions from the package manager as follows.
+
+Create directories for web-based administration ? <-- No
+General type of configuration? <-- Internet site
+Mail name? <-- server1.mydomain.tld
+ SSL certificate required <-- Ok
+
+...use your own domain name of course ;)
+
+2) Install Amavisd-new, Spamassassin and Clamav (1 line!):
+
+apt-get install amavisd-new spamassassin clamav clamav-daemon zoo unzip bzip2 arj nomarch lzop cabextract apt-listchanges libnet-ldap-perl libauthen-sasl-perl clamav-docs daemon libio-string-perl libio-socket-ssl-perl libnet-ident-perl zip libnet-dns-perl
+
+
+3) Install apache, PHP5 and phpmyadmin (1 line!):
+
+apt-get install apache2 apache2.2-common apache2-doc apache2-mpm-prefork apache2-utils libexpat1 ssl-cert libapache2-mod-php5 php5 php5-common php5-gd php5-mysql php5-imap phpmyadmin php5-cli
+
+Then run the following to enable the Apache modules:
+
+a2enmod suexec
+a2enmod rewrite
+a2enmod ssl
+
+4) Install pure-ftpd and quota
+
+First we have to make sure that the capability module is loaded in the kernel
+
+modprobe capability
+echo 'capability' >> /etc/modules
+
+Then we install pureftpd and quota.
+
+apt-get install pure-ftpd-common pure-ftpd-mysql quota quotatool
+
+echo 'yes' > /etc/pure-ftpd/conf/DontResolve
+
+5) Install mydns
+
+apt-get install g++ libc6 gcc gawk make texinfo libmysqlclient15-dev
+
+cd /tmp
+wget http://mydns.bboy.net/download/mydns-1.1.0.tar.gz
+tar xvfz mydns-1.1.0.tar.gz
+cd mydns-1.1.0
+./configure
+make
+make install
+
+
+6) Install vlogger and webalizer
+
+apt-get install vlogger webalizer
+
+
+7) Install ISPConfig 3
+
+There are two possile scenarios, but not both:
+1) Install the latest alpha 
+2) Install directly from SVN
+
+apt-get install php5-cli
+
+1) Installation of beta 3
+
+  cd /tmp
+  wget http://www.ispconfig.org/downloads/ISPConfig_3.0.0.5-beta.tar.gz
+  tar xvfz ISPConfig_3.0.0.5-alpha.tar.gz
+  cd ispconfig3_install/install/
+
+2) Installation from SVN
+
+  apt-get install subversion
+  cd /tmp
+  svn export svn://svn.ispconfig.org/ispconfig3/trunk/
+  cd trunk/install
+
+
+1+2) Now proceed with the ISPConfig installation.
+
+Now start the installation process by executing:
+
+php -q install.php
+
+The installer will configure all services like postfix, sasl, courier, etc. for you. A manual setup as required for ISPConfig 2 (perfect setup guides) is not nescessary. To login to the ISPConfig controlpanel, open the following URL in your browser (replace the IP to match your settings!):
+
+http://192.168.0.100:8080/
+
+the default login is:
+
+user: admin
+password: admin
+
+In case you get a permission denied error from apache, please restart the apache webserver process.