Apache can easily host more than one domain. And here is how.

We assume the new domain is called example.com. First we create the needed directories.
mkdir /var/www/example.com
mkdir /var/www/example.com/logs

If you are going to run web applications like a forum script or even WordPress, apache will need write access to the directories.
chown -R www-data /var/www/example.com
If Apache don’t need write access, or is hosting a dumb html page. You should still give write access to the logs folder. This is convinient for fault finding and to keep track of script kiddies.
chown -R www-data /var/www/example.com/logs

Then we need to create the Apache site config file.
vim /etc/apache2/sites-available/example.com

And modify this to suit your own domain. You can skip the ErrorLog and CustomLog if you dont want to log your site.

<VirtualHost *:80>
ServerAdmin you@example.com
ServerName example.com
ServerAlias example.com
DocumentRoot /var/www/example.com
ErrorLog /var/www/example.com/logs/error.log
CustomLog /var/www/example.com/logs/access.log combined
</VirtualHost>

<VirtualHost *:80>
ServerAdmin you@example.com
ServerName www.example.com
ServerAlias www.example.com
DocumentRoot /var/www/example.com
ErrorLog /var/www/example.com/logs/error.log
CustomLog /var/www/example.com/logs/access.log combined
</VirtualHost>

Close vim, vi, nano or what ever text editor your using. And we have to add the domain with:
a2ensite example.com

Then we have to restart Apache to apply the changes.
service apache2 restart (or you can run /etc/init.d/apache2 restart)

You should now have example.com added to your apache server.

Remember to point your dns to your web server.

Happy hosting!