For iPhone owners who are non-plussed by the iPhone 3GS and are not ready to fork out an arm and an eye for the upgrade (and who would blame you?), there is still a solution to get your old phone almost up to par with the new version:
Amazon.co.jp has on shelf a battery upgrade kit
Meanwhile, I am still iPhone-free and will happily stroll to the Softbank shop on June 26th – or maybe a week later since I will probably be too busy packing my apartment move to wait in line for a phone – and get myself a 16GB 3GS for ¥11.520 (^o^)v