Notice: I'm using Mac OSX 10.6.8

Whenever you are developing different websites or testing same website with different versions, having virtual hosts become useful. Here's the simple procedure how you can create such hosts on your local system.

First of all, you have to start Apache server. You can do it by enabling websharing:
System Prefrences —> Sharing —> Check Enable Web Sharing

Or by typing this command in Terminal.app

>sudo apachectl start

Now enable virtual hosts for the server by commenting out the following line in /private/etc/apache2/httpd.conf

Include /etc/apache2/extra/httpd-vhosts.conf

You have to give now in Apache configuration file to the default folder, which behaves like default webroot folder. In OSX these files are mostly User specific. So edit the file /etc/apache2/users/[USER].conf, to give right permissions

<Directory "/Users/[USER]/Sites/">
    Options Indexes MultiViews FollowSymLinks
    AllowOverride All
    Order allow,deny
    Allow from all
</Directory>

Now move over to /etc/apache2/extra/httpd-vhosts.conf to define the virtual hosts you want to configure by adding these lines:

<VirtualHost *:80>
    <Directory /Users/[USER]/Sites/[YOUR_WEBSITE.COM]>
        Options +FollowSymlinks +SymLinksIfOwnerMatch
        AllowOverride All
    </Directory>
    DocumentRoot /Users/[USER]/Sites/[YOUR_WEBSITE.COM]
    ServerName [YOUR_WEBSITE].local
</VirtualHost>

Now you just have to add the server name to the /etc/hosts file:

127.0.0.1    [YOUR_WEBSITE].local

Check the consistency of config file syntax by running the command

>sudo apachectl -t

If all went well, then restart the Apache server by issuing the following command:

>sudo apachectl restart

Your virtual site is finally working. Just go to your favorite browser and enter your preferred URL http://[YOUR_WEBSITE].local/ and you are ready to go!