From the GeoChalkboard blog : "In my last post I covered a simple way that you can add existing KML files to your Google Maps application through the GGeoXML class which is part of the Google Maps API. In that example we displayed an auto-updating KML file containing Global MODIS Hotspots provided by the Fire Information for Resource Management System (FIRMS) at the University of Maryland inside Google Maps. I’d like to build upon that initial post and show you how to convert this simple functionality into a Google Mapplet. Mapplets are focused, mini-applications wrapped in an XML file that run on top of the Google Maps API, and can communicate with Google Maps, fetch data from remote websites, and store user preferences. In addition, Mapplets use Google Gadget technology which gives them much of this functionality. The point of creating a Mapplet is to expose your application to Google Maps users around the world or simply to your organization."
Read more of this story at Slashgeo.