Calendar and Appointment - Repost - open to bidding

Hi, I need a person develops a system that will allow professionals to have their online calendar (1 agenda for new user). For each of the agendas site users will be able to book an appointment. The system is already used on more sites such as zoc Doc. I do not need someone to create my site, just the agendas and appointment module (maybe from Google Calendar). Do not hesitate if you have any questions.