I've got a client who has a vacation rental property website and he just wants an easy way that he can log in, click on a date on a calendar to mark it "booked" and let users view a read-only version on his site.

He pointed me to a calendar that he really liked and I was wondering if anyone knew of an existing calendar like this.

I'm not a big php programmer, but can set up basic stuff, build the db, etc. so I'm also looking for something that's easy to implement.

Any ideas would be MUCH appreciated. Here's a screenshot of the one he liked: