A local Aussie magazine is claiming that when the Eee PC 900 is released down under, it will cost AU$50 more for the Linux version. Here in the US and presumably also in Europe the price of both the WinXP version with the 12GB flash HDD and the Linux version with the 20GB flash HDD, is the same.
I think maybe the price of flash memory may be increasing, and so they are launching the one in Australia with the pricing that will also be implemented in other parts of the world. Of course, another possibility could be that Microsoft has awarded Asus with some money to sell the Linux version for more, however I doubt Asus would take such a risk, most of their customers, especially the trend setting geeky ones, would not be very approving.