I had the same question, and after doing some research I managed to find the solution!! So I thought I would post it to let everyone know...
Paste the following code into the htaccess file found in the root directory:
Code:
RewriteCond %{THE_REQUEST} ^.*/index\.php
RewriteRule ^(.*)index\.php$ /$1 [R=301]
This redirects the www.yourdomain.com/index.php to www.yourdomain.com.
The reason for doing this is for SEO purposes. The index.php is duplicate content and this will dilute the trust and authority that the search engines will give to you main page.