Yes, the bookings can be subscribed to with any calendar that supports the iCal format. The calendar then regularly retrieves the bookings from CentralPlanner and displays them as calendar appointments. They cannot be edited there.
To get the subscription link, go to the Account settings at the top right and then select the link to subscribe to the reservations. The calendar program installed on your computer or smartphone should then open and you can confirm the subscription.
To integrate your bookings into a web calendar such as Google Calendar, copy the link with right click and paste it into the desired calendar service as a web calendar.
The bookings of the past four weeks as well as for the next 18 months are included in the calendar link.