Inspired by what Rob did with geotagging Flickr, I built something similar with Where's Tim that I talked about yesterday. You can click the “Fly To With Google Earth” button and it will generate a .kml file that will open inside of Google Earth.
It wasn't that hard to generate. I used a XmlDocument to load the core .kml file (I actually renamed the base.kml file to base.xml because XmlDocument will not load a file that doesn't end in .xml) I then use a XmlNodeList to find the specific tags that need to be changed, save the xml file with an unique name and rename it back to .kml. I use a Response. Redirect to send the file back to the user and when they select “Open” in the file download dialog box, Google Earth loads and displays the location.