I had a flight with an instructor from Centennial Flight Centre in Edmonton about four years ago when I was in Edmonton for an IT Training Course. They were very friendly, helpful and accomodating. I had a great trip, but had trouble spotting the field as we came back because I was looking too far from the city for it. The airport is only four or five blocks from the first skyscrapper!
They have a website at
http://www.centennial.ca. They also have some photos from a mountain checkout ride, so it looks like Mountain Flying is possible from Edmonton, although I just went out into their Local Training Area.