Years ago, I remember John Smith's in bottles was available here. A few years ago, they introduced something called John Smith's Pub Draught, which came in those tall cans with the nitrogen powered widgets. However, I haven't seen it for a while (of course I really haven't been looking for it either). Now, I don't think they import John Smith's at all.
The brewery was bought by Scottish & Newcastle, which also owns Fosters, Baltika (with Carlsberg), Kronenbourg and, of course, Newcastle Brown. S&N has its own importing company here in the US. The local distributor for S&N imports is Chicago Beverage Systems (the Miller distributor). You might ask your local liquor store to check with CBS if the John Smith's Pub Draught in cans is still available (although I remember it really wasn't that good).