Does anyone know of a descent free Calender php script

[ksteele]

Or actually what I want to do is have the people that visit my website be able to see a calender view of my schedule and request an appt. with me for services. Some kind of auto-responder that will notify me of the request and a confirmation mail that tells them its confirmed, and again be able to see the appointment listed on the calender via my site. ANY HELP?