One of the components we are building for our Joomla 1.5 Google Based Project, is "Google Base Vehicles".

This is a full system that allows a Joomla site to be converted into a Vehicle system. Allowing Vehicle sellers of all types to advertise their Vehicles on their own site, which will automatically upload to Google via FTP, to be shown on the worlds largest Vehicle Portal for free.

www.googlebasevehicles.com
You can see the component there as it is developed. You can also login to see the admin panel
www.googlebasevehicles.com/administrator

Username = demo
Password = demo

Please have a play with it