RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.thesilverneedle\.com/$ [NC]
RewriteRule ^(.*).html$ http://www.thesilverneedle.biz/$1.php [R,L] 

RewriteCond %{HTTP_HOST} ^www\.thesilverneedle\.com/$ [NC]
RewriteRule ^(.*).php$ http://www.thesilverneedle.biz/$1.php [R,L]