threestyler on "Redirect Feeds to Feedbuner Without Any Plugin"

Can also be done via .htaccess (place before WordPress rewrite rules):

<IfModule mod_rewrite.c>
 RewriteEngine on
 RewriteCond %{REQUEST_URI} ^/?(feed.*|comments.*) [NC]
 RewriteCond %{HTTP_USER_AGENT} !^.*(FeedBurner|FeedValidator) [NC]
 RewriteRule ^feed/?.*$ http://feeds.feedburner.com/username [L,NC,R=302]
 RewriteRule ^comments/?.*$ http://feeds.feedburner.com/username [L,NC,R=302]
</IfModule>