I have created two separate RSS/Atom feeds that might be of interest to MythTV and Schedules Direct users:

They are updated once a day by a small Perl script.

You can also subscribe to these feeds by email:

Did you know there is a 'hidden' official feed for mythtv?
http://mythtv.org/backend.php

Comment by Dan
No, I didn't know about it :) Though I would still have written a new one since the official one only offers titles for each post.
Comment by François

The new MythTV site now comes with an official RSS feed:

http://www.mythtv.org/feed

Comment by François