Although Wind Mobile's web site doesn't formally say when their services will come up in Vancouver, discussions and rumours had pointed to an April 23 launch, then May, then news came that Wind Mobile has already started hiring in the area, but still there was no firm launch date to be found.
Last night while watching the Canucks/Blackhawks playoff game I saw a Wind Mobile TV commercial that carried a caption showing the list of cities already up which also said "Vancouver (Summer 2010)", so at least we have some further info to go on now. Not much, but some.
They have no announced plans for the Maritimes, meaning it's unlikely to see anything there before 2012. However, they claim to want to be Canada's third national network, and while they can maybe get away with excluding Quebec, I would imagine that to consider themselves national they couldn't exclude both Quebec and the Maritimes.
Edit: You can see here that they have licenses for spectrum in all of the Maritimes, unlike Mobilicity who holds none, so I would imagine they intend to get there some day. After Vancouver I can see Winnipeg or Halifax as the next most logical targets for new home zones. Nothing is imminent yet though.