Today I set up my laptop in an office where a 15" TFT screen was available, so I decided to try dual screen setup on my laptop using the VGA connector on my laptop.

The standard Xinerama for dual head that I used in another setup did not work. I decided to search for laptop vga and finally for "xorg laptop sis xinerama", which lead me to a website dedicated to sis drivers and it's native "MergedFB" mode. This worked perfectly, although I haven't found a way to make the laptop screen the primary one, but it's a lot better than one screen :-)

here's the xorg.conf
Keep in mind, this is a Sis setup, so it won't work with other cards!