We can use Mu to setup multi wordpress blogs. If you do not want to do so, you can use wordpress to setup multiy blogs also.
 For example, we want to set up two blogs: www.glassespeople.com ,and http://blog.glassespeople.com, we only add the following code at wp-config.php:
if($_SERVER[“HTTP_HOST”]==”www.glassespeople.com” || $_SERVER[“HTTP_HOST”]==”glassespeople.com”){
define(‘DB_NAME’, ‘www’);
define(‘DB_USER’, ‘www_usr’);
define(‘DB_PASSWORD’, ‘www_psw’);
define(‘DB_HOST’, ‘localhost’);
define(‘DB_CHARSET’, ‘utf8’);
define(‘DB_COLLATE’, ”);
}else if($_SERVER[“HTTP_HOST”]==”blog.glassespeople.com” || $_SERVER[“HTTP_HOST”]==”blog.glassespeople.com”){
define(‘DB_NAME’, ‘blog’);
define(‘DB_USER’, ‘blog_usr’);
define(‘DB_PASSWORD’, ‘blog_psw’);
define(‘DB_HOST’, ‘localhost’);
define(‘DB_CHARSET’, ‘utf8’);
define(‘DB_COLLATE’, ”);
}
 One more example:
$hostname = $_SERVER[‘SERVER_NAME’];
$hostname = str_replace(‘www.’, ”, $hostname);
// switch($_SERVER[‘HTTP_HOST’])
switch($hostname)
{
case “ozoptical.com”:
$table_prefix = ‘wp_’;
break;
case “eyeglassesshop.com.au”:
$table_prefix = ‘eyeglassesshop_’;
break;
case “discountglasses.net.au”:
$table_prefix = ‘discountglasses_’;
break;
case “eyeglassesonline.net.au”:
$table_prefix = ‘eyeglassesonline_’;
break;
case “discounteyeglasses.net.au”:
$table_prefix = ‘discounteyeglasses_’;
break;
case “cheapeyeglasses.net.au”:
$table_prefix = ‘cheapeyeglasses_’;
break;
case “buyglasses.net.au”:
$table_prefix = ‘buyglasses_’;
break;
case “glassespoint.net”:
$table_prefix = ‘glassespoint_’;
break;
case “zennioptical.com.au”:
$table_prefix = ‘zennioptical_’;
break;
case “selectspecs.com.au”:
$table_prefix = ‘selectspecs_’;
break;
case “glassescrafter.com.au”:
$table_prefix = ‘glassescrafter_’;
break;
case “eyebuydirect.com.au”:
$table_prefix = ‘eyebuydirect_’;
break;
case “ozoptical.com.au”:
$table_prefix = ‘ozopticalau_’;
break;
case “ozoptical.net”:
$table_prefix = ‘ozopticalnet_’;
break;
case “ozeyeglasses.com”:
$table_prefix = ‘ozeyeglasses_’;
break;
case “ozspectacles.com”:
$table_prefix = ‘ozspectacles_’;
break;
case “ozspectacle.com”:
$table_prefix = ‘ozspectacle_’;
break;
default:
$table_prefix = ‘buyeyeglasses_’;
break;
 }