Dave Winer has started a new site called Share Your OPML.

The purpose of this site is to gather a community of subscription lists, in OPML format, and aggregate them in interesting ways.

The site is very simple to use and I was easily able to upload my Bloglines OPML by entering the URL of my public feeds.  The site also provides a sort of reverse look-up which allows you to easily see who is subscribing to a feed.   It's good to be able to see all 3 people that might be subscribed to your feed and thank them personally.