Geo::IP::PurePerl and HTML::GoogleMaps to display your comments on a google map. To use it, you need to install the two previous perl modules, and to copy paste your Google Map API key in the plugin settings. Then you can create a new index page with the following code:
<$MTCommentMapHead$> <$MTCommentMapDiv$> <$MTCommentMapScript$>
The <$MTCommentMapHead$> tag may take the following arguments: blog_id, height, width, zoom, type, lastn, max_comments_per_bubble.
Note that the free Geo::IP database is not very accurate, I’m not living in Lyon ;-)