This plugin is promising but was difficult to tame.
It seemed to have a bug. In order to add a post to the calendar you have to check the category that you created (like "event") for flagging post that show up on the calendar. Unfortunately, something in the plugin was disabling the category, so I couldn't selected it ("event") from the post interface.
After installing and activating, I added the plugin to my site by dropping the code into the sidebar.php file. That went okay.
I don't like the fact that the iCal feature cannot be disabled. Why the iCal feature just downloads to a file is puzzling. It seems to me a lot easier just to type the event into my calendar. Anyway, I'm not intending to use this as a public calendar. So my preference would be to disable the iCal code.
This plugin was promising. It looked great. I wish it worked for me.