The best and easiest way to get around the city of Calgary is to use their train system. The train system runs throughout the city. You can either buy a one time pass that is good for an hour and a half or you can buy a day pass, which is the way to go if you plan on using the system throughout the day. The passes can be purchased throughout the city or online before you go. The trains run regularly, are very clean, are safe and the system itself is very easy to navigate. We enjoyed using this to get around while we were there.
The airport is the best way to get into the area from the states.