Never done the Campfire program, but sure sounds fun. If you can't get the info you are looking for here, try posting on the Camping in Disney World board here. I'm sure someone there will know the details
The campfire is held every evening beginning at 7pm or 8pm depending on daylight savings. There will be a sing along and visit from chip & dale before a disney movie is played. This is a free activity and for the movie schedule call the week you will be attending. The automated menu will give you the listing or you can contact the Front Desk who has the schedule for the current month.
The campfire program is open to all WDW resort guests. It generally begins around 7:00 pm during the fall/winter season and 8 pm after the time changes in April through the summer. It is held near the Meadow Trading Post in the campfire area. The program begins with a sing-a-long led by a Disney CM and a marshmallow roast around two campfire rings. You may bring your own marshmallows or buy them at the Chuckwagon (roasting sticks and marshmallows are $2). You may also buy pizza, hot dogs, candy, nachos, juice, popcorn, cokes, coffee, beer and other refreshments at the Chuckwagon. While this is going on, Chip and Dale make an appearance to visit with guests and sign autographs. The sing-a-long lasts about 30 minutes. Next, one or two Disney animated features, depending upon the season, are shown on a large outdoor screen. Seating is available in bleachers or on benches. There is also plenty of room to lay out a quilt or blanket. The movie schedule is posted at all comfort stations. In the event of rain, the sing-a-long is still held on the porch of the Meadow Trading Post.