It appears that Asustek, Hong Kong, have decided to offer users free upgrades of the Eee PC 900 batteries due to a slip-up that saw reviews and presentations include a larger capacity battery than was actually shipped. While this is good for Hong Kong, it may not apply to the rest of the world. ASUS are also saying that the standard battery for the Eee PC 900 will be the 4400mah version.
Via jkkmobile.