Like Dominique, I found something free and not useless at the Paris Autumn Stampshow : Saint Pierre and Miquelon 2008 philatelic programmation.
As always, a large part is about local history, geography and fauna/flora.
For the secret of the postal rates, go to La Poste website for the archipelago located near Western Canada. You will see that most of the French Marianne definitives issued there overprinted are not useful on their own.
Inside the islands, rates are adapted to the littleness of the territory : 30 eurocents for the less than 20 gram letter, 53 cents for the less than 100 grams (remind that 0,54 € is the national 20 gram letter in Metropolitan France).
Mail is distributed only in postal boxes (boîte postale ; "BP" and a number on the adress) located inside the post office of Saint-Pierre. Do not forget this number when you write to the French oversea territory. Postal box BP 4100 is the poste restante.
Concerning the philatelic history, I advice local expert Jean-Jacques Tillard's french/english website.