Samsung's Galaxy S was the best selling phone in Japan last week, knocking the 32GB iPhone out of the top spot for the first time in 18 weeks, according to The Chosunilbo. The data comes from Japanese market researcher BCN.

The 16GB model of the iPhone was the third best selling phone in Japan, so the iPhone as a whole is still likely outselling the Android-based Galaxy S. It was the first week the Galaxy S was available so it's hard to say whether the sales are due to initial excitement for something new or if it's a sign of things to come. Nevertheless, it's a huge success for Samsung, and Google, as it means the Android device is becoming the "phone to have" in Japan and not simply just another iPhone alternative.

In related news, the Galaxy S smartphone is now listed as the first device to get Wi-Fi Direct certification, according to the Wi-Fi Alliance (via Zats Not Funny!. Since Wi-Fi Direct is largely software based, many recent devices are upgradeable; certification can be applied retroactively, so all we have to do now is wait for Samsung to release the appropriate firmware upgrade.

Samsung is expecting to sell more than 40 million smartphones worldwide in 2011, according to Nikkei, which cited a senior official at the South Korean company. That is double the projection for the current year, which has been increased from 18 million to 20 million units.