Apple proclaimed on 14th April that they are planning to release iPad internationally by the end of May as the demand for iPad increased abruptly exceeding their expectations. After the debut release of iPad on April 3rd, it created a tremendous demand in the market as the sales exceeded nearly 300,000 and in the first week the sales shot up over 500,000. As you already know Apple has taken preorders for the 3G models that are to be delivered late April.
With the unexpected demand for the iPad, Apple has thus taken decision to postpone the release of iPad for international market by the end of May, so it can provide the product to all the global consumers. Most probably, on May 10th the international price may be revealed and preorders will be taken for iPad. Even as most of the international customers are disappointed on the news, it is understood that the delay for supply is because of the extreme surge in demand for the iPad.
