API to post listings to AutoTrader.com Cars.com Edmungs.com

I would like a programmer that has done this before or has a script avaialbe. I cannot seem to find documentation anywhere about api posting listings to any of these services. [login to view URL] [login to view URL] [login to view URL] [login to view URL] [login to view URL] I would also like to submit the inventory to all the free classified sites with this script, Maybe someone has done this before for a dealer managemant system. I only care about api/intergration via submitting to the top paid classified sites and free classified sites.