DOUBLE DECKER TOUR BUS - We got their tour package that includes the transportation to most places of interest at your own pace (buses came by every 20 minutes) and included admission to Maid of the Mist, the Aerocar, and the Journey Behind the Falls. It was $78 US dollars/$110 Canadian for the tour and every cent was well spent. Every place that we visited was a part of the tour.
http://www.infoniagarafalls.com/
(photo is from this site)

