An American who acts like a Canadian (says 'eh' alot, watched the NHL, supports Canadian sports teams, says 'aboot', etc.) or an American who wants to live in Canada. The term comes from the belief that someone in this condition is believed to be in Canada or in the mind of a Canadian, thus an Am (American) is in the Can (Canada).
Am in the Can male: So you really got dumped by your boy friend, eh?
Regular American young woman: Yep.
Am in the Can male: Well that's too bad, you know we can talk aboot this later you know okay, eh? Wanna watch some hockey eh? My Maple Leafs are facing the Red Wings tonight, eh, wanna watch the game with me, eh?
Am in the Can: I wanna move to Canada, Texas really sucks you know, eh?