Have been working to put together a Google Map of Make Poverty History local groups on the website.
What has been wonderful so far is how simple the whole process has been. Using the fantastic Gmap module, the Location module and our 5.7 Drupal install it took a few hours to create the Google map here.
Two more things:
1. I am looking to create a Google Map-enabled photo-petition just like this one at enoughfear.org
2. This is an excellent screencast on the process of Drupal/Google Maps integration. So easy, so fun!