Display Calendar

Please look at http://rkassoc.net/Rainrich/index.php?comm=Greenlawn

Note the empty area to the left. Note that the visitor is given several days from which to choose an appointment.

I would like to have a visual calendar (maybe more than one month) in the blank space. This will be for reference only; no functionality. I would like the ability to shade background of the days available in one color (for example, green) and the other non-available days in gray.

Since this is all php, I could build the displayed calendar (based on months / days available) when the page loads.

Is there something like this available?

Thanks