http://homeaway.com/index.cfm/tgt/HA_products
From the About Us page:
The good news is that perhaps, oh please oh please, h-r will eventually move to the rentors.org calendar so that I don't have to update their stinky proprietary one. The bad news is that I fear rentors.org will soon no longer be free.HomeAway is the world's most complete marketplace of vacation rental properties, representing over 50,000 vacation rental homes, condos, guesthouses, cottages, and cabins in over 45 countries. HomeAway incorporates the inventory from several of the most respected vacation rental listing collections on the Internet, all owned and operated by WVR Group, Inc. (CyberRentals, H-R, GreatRentals, A1Vacations, FeWo-direkt and TripHomes)...
All WVR Group Web Sites are members of Rentors.org. The purpose of Rentors.org is to provide owners of vacation rental properties with universal calendars and guest books that can be used on any web site.
fyi,
debk