Basically you can point any domain's A record to 174.129.25.170 and it will redirect you to the www subdomain.
Options +FollowSymlinks RewriteEngine on rewritecond %{http_host} ^ec2instances.info [nc] rewriterule ^(.*)$ http://www.ec2instances.info/$1 [r=301,nc]
Basically you can point any domain's A record to 174.129.25.170 and it will redirect you to the www subdomain.