Do you simply want people to see what dates are either booked or available? If so, could you simply use one of the event modules and create events listing either booked or available? I know that Event Calendar allows you predefine event types. Could you have 2 event types for available or not?
Hi marathoner,
if a non-WB-solution is ok, have a look at this
http://www.rentcalendar.com/Regards
albatros