If I am moving somewhere in Canada that has a different area code, will I be charged long distance for calls, if my plan includes Canada wide calling? Will other people trying to call me be charged extra?
On your end, you will not be charged, Canada-Wide is truly Canada-Wide.
If you keep the same number, people in your current area will not be charged long distance as they're still calling a number that originates in that area, but people in the new area will be calling long distance.
If you change the number, people in your current area will be charged long distance (unless they're covered), but not the people in the new area.