By setting up your google calendar details (email address/password) any bookings created on this web site will be written to your Google calendar. By using tools freely available from Google these details can then also be syncronised onto your smartphone (iPhone, Android, WP7 etc) and also into your desktop Outlook calendar.
NOTE - any changes you make to appointments directly on your Google calendar will not be reflected back to this web site, any booking amendments/cancelations MUST be done via this web site and they will then be syncronised to Google calendar.