Open Sandwich Design can provide availability calendars in many different formats to match your requirements and website. One example can be seen on The Dambridge Oast website.
There can be advantages, website visitors can make a booking enquiry secure in the knowledge that the period they want is available.
But - there is a downside - if a visitor sees that week, day, month is not available, they won't hang around, they'll just go to another website. At least without the availability calendar, you have the flexibility to discuss other possible options with the customer.
Booking online can be great for website visitors but very often a would-be guest wants to ask some questions and appreciates the personal touch, so if you have online booking, alternative choices of phone contact and an ordinary email enquiry form are essential.
A fax is also a good idea because organisations such as booking.com take the guests booking through their website, then fax the details and credit card number to you. You can have a 'book online' button on your website that goes to a page on booking.com. Also note that many online booking websites and systems, such as Eviivo, can charge up to 15% commission per bookiing.
We like a booking system we recently implemnted for one of our clients - see Molland House website - no commission is charged, the client pays a flat anual rate to be included in various online directories, and the booking system could be nicely integrated into the existing website.
Of course, you could go for the full blown reservation system where offline and online bookings are automatically synchronised but usually these integrated frontdesk systems are expensive.
A booking enquiry form such as the one on the Dambridge Oast website, or the Salmestone Grange website, with or without an online availability calendar still works well for the smaller bed and breakfast or self catering accommodation - you have personal interaction with the customer and don't have the hassle of making sure the online bookings tally with the offline bookings and so on.
One last tip - make sure you get some good reviews on such websites as Trip Advisor for example - people will want to stay with you whether you have on line booking or not.