Kill it with fire.
WP Burner
A low-impact FeedBurner feed redirection plugin for WordPress, using Apache .htaccess files instead of the PHP engine to perform redirection.
FeedBurner
FeedBurner is a nice enhancement to any WordPress blog, providing subscription statistics, analytics, and publicizing tools. If you run a blog, FeedBurner is definitely worth a look.
FeedSmith
The fine folks at FeedBurner provide the FeedSmith plugin to provide integration with WordPress. If FeedSmith works properly for you, then you can stop reading now.
Seriously. Move along, nothing to see here.
The Nerdy Bits
I had trouble with the reliability of the FeedSmith plugin; some of my readers were complaining of strange errors, and my error logs contained messages indicating that FeedSmith was attempting to set a header after a response had already been committed.
HTTP transactions are composed of headers and content. Headers are sent before content; once the server starts sending content, then the transaction is said to have committed, which means that further headers can't be sent.
FeedSmith works by setting an HTTP 302 'moved temporarily' redirect header so that your feed gets redirected to FeedBurner without you losing control of your feed. To perform the redirect, there can't have been anything but header information sent already, or the transaction is very likely to have committed, i.e., it's now in the content state and one can't modify the HTTP headers any more.
Tracing back the errors present in my error log indicated situations in which the server had already started sending content when the FeedSmith hooks were invoked, so attempting to set a redirection header as FeedSmith does wasn't going to work.
My conclusion is this: I'm not sure why FeedSmith should actually be working anywhere. In fact, using a random sampling of many sites using it, a curl trace shows it not to be working properly in many cases.
Solution
I think the better choice is to handle the FeedBurner redirect via an .htaccess rewrite, which is what WP Burner does.
As a bonus, this is very efficient, as the PHP engine is never invoked.
Since mucking around in .htaccess files isn't something that most want to deal with, this small plugin serves to maintain appropriate rewrite rules in a pleasant manner.
License
WP Burner is released under the terms of the GNU General Public License, version 2.
Current Release
release: 1.2
filename: wp-burner.1.2.zip
md5sum: 22d2bd9e7fce4eaf84e209ff5e88aab6
Version History
1.2 - 10/21/2009 - Handle feedburner.google.com conversion
1.1 - 12/20/2008 - Version bump for WordPress 2.7.0
1.0 - 11/16/2008 - Initial public release