Although not directly related to Movable Type, many bloggers I know have been asking for such a tool. The Newsgator Toolkit is an extension for Mozilla Firefox that will eventually provide you with a series of complex and powerful tools that will make it even easier to use Newsgator.
For the moment, however, it simply sits in your statusbar and acts as a notifier displaying the number of unread posts and giving you a detailed view of which feeds have been updated.
More information is available on my personal blog.
Note: This version is completely unsupported, please do not email me any bug reports or support requests (something many people have taken the liberty of doing the past few days!) or post to the support forums.