Many hotels offer Internet service -- some complimentary and some for a fee. There are cybercafés scattered throughout the island and Wi-Fi hot spots on the boardwalk behind Front Street in Philipsburg.
The main Dutch-side post office is on Walter Nisbeth Road in Philipsburg. There's a branch at Simpson Bay on Airport Road. The main post office on the French side is in Marigot, on rue de la Liberté. Letters from the Dutch side to North America and Europe cost NAf 2.85; postcards to all destinations are NAf 1.45. From the French side, letters up to 20 grams and postcards are EUR .58 to North America. When writing to Dutch St. Maarten, call it "Sint Maarten" and make sure to add "Netherlands Antilles" to the address. When writing to the French side, the proper spelling is "St. Martin," and you add "French West Indies" to the address. Postal codes are used only on the French side.
Coconets (29 Hope Estate, Grand Case). Cyber Link (53 Front St., Philipsburg). Internet Corner (105 rue de Hollande, Marigot).