It's a little known fact that Canada was on the verge of invading the islands during World War 2. It was feared that with the fall of the French government to the Nazi's that the Vichy French and Germany would make use of the islands for intelligence gathering (mainly for Western Atlantic submarine and convoy reconnaissance) and eventually even as a springboard for invading North America.
The American and Canadian governments (including the active knowledge and participation of the respective President and Prime Minister) agreed that the inlands should be taken, and the Canadian military drew up plans (since made public) for such an operation. The Canadians were not expecting much if any resistance, so it was basically a matter of landing troops with sufficient naval and air cover, and taking over government from the Vichy 'loyal' garrison and whatever local resistance might arise. To further reduce the chance of resistance it was suggest in their plans that the Canadians could use merchant (as opposed to military) vessels in their invasion, contributing to its surprise and also (hopefully) arousing less hostility among the natives.
Further complicating this difficult and delicate situation was the condition of the islanders themselves. The islands weren't (and still aren't) self sufficient, and they relied on the mother country for support. The subsidy, which they received from France, had shrunk and then stopped since the fall of the home government. While some of the islanders had savings, most did not and were nearing starvation.
However, the Canadian invasion was not to be. It was arranged that the Free French (someone should really node Free French) under de Gaulle would take the islands, which they did on December 24th 1941. Even after the invasion, the problem of feeding the people was still not solved. The Free French tried to collect enough money, but there was still a major shortfall.
An ingenious, and not altogether legal, scheme to raise money for the islanders was devised. The Free French on the island printed stamps (under the 'authority' of the government of St. Pierre and Miquelon) worth tens of thousands of dollars at face value (a lot of money then) and sold them at a discount in Canada and the US (which wasn't a bad deal for the French considering they weren't worth anything in the first place). Most were intercepted and destroyed, but they did raise in the range of 20 to 30 thousand much-needed dollars for the islands.
It's still interesting to think how close Canada came to actually acquiring territory in World War Two. They were probably the only ally who didn't (and this includes lesser allies such as Australia and New Zealand who acquired various island possessions and protectorates). Also of note is the fact that Newfoundland was not at this point a part of Canada (it didn't join Confederation for another 8 years) and so the islands would have been a geographical anomaly for Canada in the opposite sense they are today.
Then again, the islands would probably have been returned to the French after the war anyways like their other pre-war possessions were (Vietnam for example).
Additionally, such a takeover would have avoided the recent fishing conflicts with the French government and probably would have resulted in better living conditions for the islands residents (while Canada and France both subsidise their Atlantic "possessions", Canada is more generous). Then again, if the colony were to have been attached to Quebec (which would have been a distinct possibility) the residents there would have gone a long way towards tipping the scales in favour of the 'Oui' (Yes) side in the recent separation vote, so I guess it swings both ways :)
You can find information on St. Pierre and Miquelon in WW2 at http://www.st-pierre-et-miquelon.com/1942/english.html (most of the information is in French however), including the 'infamous invasion plans', and more about the islands in general at http://www.st-pierre-et-miquelon.com. | 
