Generally, if it is a local call from a landline where you are standing, then it's a local call with a cellphone in your hand.
So, if you're in downtown Ottawa using a landline, you can call Gatineau without being charged long distance, but will probably encounter long distance charges if you call Kingston or Mt. Tremblant. So, if you use a cellphone in downtown Ottawa, regardless of the carrier, the same rules should apply.
In some cases the local calling area of cellphones ends up being larger than the local calling area of landlines, but my guess is that Kingston to Mt. Tremblant is a little on the large size.