1. Move your Wiki to a sub directory of your site, for instance /w
2. Create .htaccess in root directory, that is / and add the following lines to it:

RewriteEngine on
RewriteRule ^wiki/?(.*)$ /w/index.php?title=$1 [L,QSA]

3. Open your LocalSettings.php and add the following lines to it:

$wgScriptPath = “/w”;
$wgScript = “/wiki”;
$wgArticlePath = “$wgScript/$1″;

4. Done.

Before you try this, please make sure you have enabled the rewrite feature of your Apache. and what the most important is: when you enabled rewrite in httpd.conf, you must stop it and start it. please note, if you just try ‘restart’, it won’t work. i was stuck here for a loooog time.