A typical course blog on one of our servers generates RSS like the following:

<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0">
<channel>
<title>Blog</title>
<link>http://learnacct.open.ac.uk</link>

The link here should be to /mod/oublog/view.php (with the id parameter for the correct blog).