Softbank, the No. 3 wireless provider in Japan, on Wednesday said it has agreed to offer the Apple iPhone, taking the smartphone into one of the world's most demanding mobile markets.

Softbank announced the deal in a terse, one sentence release. "Softbank Mobile today announced it has signed an agreement with Apple to bring the iPhone to Japan later this year."

The announcement comes less than a week before Apple holds its Worldwide Developers Conference in San Francisco. Chief executive Steve Jobs is expected to introduce during his opening keynote a new version of the iPhone that operates on carriers' third-generation, often referred to as 3G, high-speed data networks. The current iPhone works on slower EDGE cellular networks, placing it at a disadvantage in European and Asian countries where people are use to using peppier smartphones.

The latest announcement is important for Apple to reach its goal of selling 10 million iPhones, which would amount to about a 1% share of the global cellular phone market, by the end of the year.

The Japanese use their mobile phones for far more tasks than their counterparts in the United States. In Japan, the devices are used to watch TV, pay bills, order concert tickets, read comics, and find locations through applications based on global-positioning satellites. While the iPhone will not meet all the criteria initially, researchers for the think tank Nomura Research Institute told USA Today that Apple could sell 2 million to 3 million iPhones annually in Japan, which would amount to about 5% of the market.

Japan's other major wireless telecom providers, NTT DoCoMo and KDDI, have reportedly expressed interest in selling the iPhone, but no deals have been struck. There's no indication that the Softbank deal is exclusive.

Also on Wednesday, Spanish telecoms company Telefonica said it would start selling the iPhone in Spain this year. The company's O2 mobile unit has been selling the smartphone in Britain since last November.

The iPhone is expected to be available in Spain before the summer, the Reuters news agency reported. Telefonica's two main rivals, Vodafone and Orange, have said they will not sell the device in Spain, making Telefonica the only provider.