This is something you may have to have custom made based off your business logic because there are a few different things that may need to happen. If you want to reserve rooms only after someone has given a deposit or paid then you need to send a request to a payment system & get a response before removing one of the available rooms. Will you want guests to be able to have an account to see their reservation information, edit, or cancel? If you dont want to have something custom built then there are a number of hotel booking systems that you might want to look into. http://sirvoy.com/ , http://www.globekey.com/