Sarah and I worked on a Google Earth Network Link this morning. This one passes the current extent (BBox) of Google Earth to a PHP page, which queries a database for WeoGeo datasets within that extent. In the image below, push-pins show the NW corners for the USGS Topo maps in the Tampa Bay area. An info bubble from each push-pins has the dataset description, a link to the purchase page, and a link to the Low-Resolution KML. One of those low-res KMLs is also visible in the image below.

I’ve just converted my Flickr RSS feed, which has GeoRSS tags, to a KMZ file for viewing in Google Earth.
The KMZ is here:
http://dye.daniel.googlepages.com/Dans_Flick_RSS_Feed.kmz

The tool I used is described here:
http://www.nearby.org.uk/blog/2007/04/30/rss-georss-to-kml/

and located here:
http://www.nearby.org.uk/rss-to-kml.php

Geonames also has tools for this:
Geonames RSS to GeoRSS Converter

Have fun!