It took too damned long to find information on how to enable the advanced editing toolbar in a standalone installation of mediawiki 1.18+ so hopefully google brings you here and this will save you time. One would think that changing the editor toolbar to be similar to the toolbar in wikipedia would be considerably easier but searching for information in regards to changing the toolbar was nightmarish at best.
Basically you add 4 lines of code to your LocalSettings.php
#Enable advanced editor
require_once( “$IP/extensions/WikiEditor/WikiEditor.php” );
$wgDefaultUserOptions['usebetatoolbar'] = 1;
$wgDefaultUserOptions['usebetatoolbar-cgd'] = 1;
$wgDefaultUserOptions['wikieditor-preview'] = 1;