I have the following code in my .htaccess file, to omit the file extension .php in the url for each file:

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^(.*)$ $1.php

Right now, I have pages in the search engine show up with both the .php and without. How can I make sure it will show up without?
Also, I have two more problems.
How can I make sure the search engines only display my site without the www?
How can I make sure the search engines display http://mysite.com instead of http://mysite.com/index or http://mysite.com/index.php

Thanks!