If memory serves me, it is in your Options.
EDIT: The author has more information available on his site: http://www.semiologic.com/software/subscribe-me/
I went into the script and modified this section (I expected things to blow up, but it seems to be working):
'bloglines' => 'http://www.bloglines.com/sub/%feed_url%',
'yahoo' => 'http://add.my.yahoo.com/rss?url=%feed_url%',
'google' => 'http://fusion.google.com/add?feedurl=%feed_url%',
'msn' => 'http://my.msn.com/addtomymsn.armx?id=rss&ut=%feed_url%&ru=%site_url%',
'aol' => 'http://feeds.my.aol.com/add.jsp?url=%feed_url%',
'rojo' => 'http://www.rojo.com/add-subscription?resource=%feed_url%',
'feedlounge' => 'http://my.feedlounge.com/external/subscribe?url=%feed_url%',
'newsgator' => 'http://www.newsgator.com/ngs/subscriber/subext.aspx?url=%feed_url%',
'netvibes' => 'http://www.netvibes.com/subscribe.php?url=%feed_url%'
);
Everywhere you see this: %feed_url% change that to your feed. For example, if you use a Feedburner feed, change it to that full Feedburner url.