Gizmodo: The ASUS S121 is simply a larger version of its S101 netbook. There is next to nothing in terms of additional information regarding the specs. But.
The S101 has a smaller 10.2″ LCD with a 1024×600 pixel format and uses an Intel Atom to turn the show. The S121 sports a 12.1″ TFT LCD with a pixel format of 1280×800. I think a safe best is that the S121 will also be Atom-based. The 1GB max in the S101 will probably be increased to 2GB; the 64GB SSD up’ed to 128GB SSD. I will also guess that the OS will be going from XP/Linux to Vista/XP/Linux.