This site uses a Google Map to display Last Minute Vacation Rentals, which they define as rentals that available in the coming two-week period (sounds appropriate to me). Last minute rentals are not necessarily a Web 2.0 phenomenon, but the use of Google Maps is. All you do is click on the Map Pin to get an instant pop up of the property -- incredibly fast, fun and easy to use! They don't have a lot of properties up at the moment, probably because they are so new.
I think we will soon be seeing more of these kinds of mapping applications beyond the last minute travel realm.