Subdomain vhost_alias

.htaccess

<IfModule mod_rewrite.c>
    RewriteEngine on
    RewriteBase /

    <rewrite rules here>
</IfModule>

default

<VirtualHost *:80>

    ServerAdmin youremail@domain.com

    ErrorLog ${APACHE_LOG_DIR}/error.log

    LogLevel warn

    CustomLog ${APACHE_LOG_DIR}/access.log combined

    <Directory /path/to/web/dir>
        Options FollowSymLinks MultiViews
        AllowOverride All
    </Directory>

    UseCanonicalName Off
    VirtualDocumentRoot /path/to/web/dir/%1

</VirtualHost>

zonefile

*			A	<ip addr>