Jef gives some additional background on GeoRSS and the map creation process for Google and Yahoo!:
GeoRSS is a simple XML-based file format used for adding location information to data items. It is based on RSS 2.0, plus a couple additional elements -
and - that let you specify the geographical location of each
So, this page tries to give you the best of both worlds. It reads the same XML data files used by Yahoo! Simple Maps, does the same geocoding, but it displays the data as a Google Map. This lets you combine the ease of creating a Yahoo! Simple Map with the nice user-interface of a Google Maps app.
Here are some maps that have been created using this:
Don't forget Jef's other Google Maps creations:
Paris Star Forts
Transpac 2005 Tracks