I'm assuming replace "mydomain" with my actual domain name?

I'm getting duplicate content warnings for my site because the same pages are getting crawled twice? Once with http://www.website.com and once with http://website.com. I'm assuming this is a .htaccess problem so I'll post what mine looks like.

I think installing WordPress in the root domain changed some of the settings I had before. My main site is primarily in HTML with a blog at

http://www.website.com/blog/post-name

BEGIN WordPress

<ifmodule mod_rewrite.c="">RewriteEngine On
RewriteBase /
RewriteRule ^index.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]</ifmodule>

END WordPress