We were just at FW this past Feb and caught many of the movies. The sing-a-long started at 7pm (times may vary, check for when you are going to be there) and the movie started after. Chip and Dale make the rounds for photos and autographs too. You can buy smores kits and marshmellows and sticks (sorry can't elaborate more, we brought our own). Depending on the time of year and day of the week, there may be 2 movies shown. If you watch on this board you will see someone post a thread about the schedule at the beginning of each month.
While I have been told that this is intended for onsite guests only, there is no one at the campfire who checks this that I saw when we were there. I'm not sure about gaining entry into FW through the main gates if you are not a Disney resort guest...maybe someone else can help on that one.