Calendar style availability script

I want a simple PHP script written to show the availability of my holiday villa on my web site (not a booking script). I need to be able to manage it through some sort of simple interface. I would envisage the front end just showing a calendar with a simple colour coding across the date ranges e.g WHITE [available] ORANGE[provisionally booked] BLUE [booked] and an e mail link to inquire about a booking. The back end needs a simple page that allows me to update the calendar as described above.