I found a script somewhere on the internet, then modified it to fit my needs. Some of the comments in it may be inaccurate, as I did not update them from the orignal comments. Just copy all of this to a text file, give it the .sh extension, and make it executable. I have only tested this on a default install of Ubuntu 10.04 with LAMP:

#!/bin/bash

# This script is used to create virtual hosts.

echo "Enter the username you want created (use domain name)"

read usr

echo "Enter the home directory you want created (/home/www/$usr)"

read homedir

echo "Enter ServerName (domain name, microsoft.com, ubuntu.org"

read sn

echo "Enter ServerAdmin email"

read se

# Create the web directory and a index.php test file

mkdir $homedir

cd $homedir

mkdir $sn

cd $homedir/$sn

mkdir "public_html"

cd $homedir/$sn/public_html

echo "<?php echo '<h1>$2</h1>'; ?>" > $homedir/$sn/public_html/index.php

# Set the owner and change permissions

chown -R ftpuser:www-data $homedir/

chown -R ftpuser:www-data $homedir/$sn/

chmod -R '750' $homedir

chmod -R '750' $homedir/$sn/public_html

# Create a directory for your apache errors log

mkdir /var/log/apache2/$sn/

# Creation the file with VirtualHost configuration in /etc/apache2/site-available/

echo "<VirtualHost *:80>

        ServerAdmin $se

        ServerName $sn

        ServerAlias www.$sn

        DocumentRoot $homedir/$sn/public_html/

        <Directory />

                Options FollowSymLinks

                AllowOverride All

        </Directory>

        <Directory $homedir/$sn/public_html/>

                Options Indexes FollowSymLinks MultiViews

                AllowOverride All

                Order allow,deny

                allow from all

        </Directory>

        ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/

        <Directory "'/usr/lib/cgi-bin'">

                AllowOverride All

                Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch

                Order allow,deny

                Allow from all

        </Directory>

        ErrorLog /var/log/apache2/$sn/error.log

        # Possible values include: debug, info, notice, warn, error, crit,

        # alert, emerg.

        LogLevel warn

        CustomLog /var/log/apache2/$sn/access.log combined

    Alias /doc/ "'/usr/share/doc/'"

    <Directory "'/usr/share/doc/'">

        Options Indexes MultiViews FollowSymLinks

        AllowOverride All

        Order deny,allow

        Deny from all

        Allow from 127.0.0.0/255.0.0.0 ::1/128

    </Directory>

</VirtualHost>" > /etc/apache2/sites-available/$sn

# Add the host to the hosts file

echo 127.0.0.1 $sn >> /etc/hosts

# Enable the site

a2ensite $sn

# Reload Apache2

/etc/init.d/apache2 reload