The both domains are yours or one is yours and one belongs to someone else and you've checked the content with copyscape?
If you have multiple domain names but only one website, you can add a permanent 301 redirect in an index.php file to the 'extra' sites to point to your main site Just create a file named index.php containing the following text: <? Header( "HTTP/1.1 301 Moved Permanently" ); Header( "Location: http://www.yourmaindomain.com" ); ?> This is useful if you want to buy .net .org and .info versions of your main .com domain Simply replace yourmaindomain.com with whatever your main domain name is and add this index.php file to the root directory for each domain That way you only have one site to manage