Well I thought I’d have another play with Nouveau the open source driver for nVidia GPU’s, as it been a while since played around with them. Since the last time I played with Nouveau it was very buggy and unstable and 3D support was even worse, but I very surprised that there is some 3D support via Gallium3D.

Anyways this how I setup my xorg.conf for dual head setup with nouveau under Debian testing (wheezy):

Section "Monitor"
          Identifier   "monitor0"
          Option       "PreferredMode" "1920x1080_60.00"
EndSection

Section "Monitor"          
          Identifier   "monitor1"
          Option       "PreferredMode" "1440x900_60.00"
          Option       "RightOf" "monitor0"
EndSection

Section "Device"
    Identifier 	       "device0"
    VendorName         "nVidia Corporation"
    BoardName          "GeForce GT 220"
    Driver  	       "nouveau"
    Option  	       "Monitor-DVI-I-1" "monitor0"
    Option  	       "Monitor-VGA-1" "monitor1"
EndSection

Section "Screen"
    Identifier "screen0"
    DefaultDepth 24
      SubSection "Display"
        Depth      24
        Virtual 3360 1080
      EndSubSection
    Device "device0"
EndSection

Section "ServerLayout"
    Identifier 			"layout0"
    Screen 			    "screen0"
EndSection

At the moment I am very happy with Nouveau and going to keep using it till it borks it again

Also if you not want to go through the hassle of xorg.conf you could run or put this in your session startup file, example this what I used for testing with ~/.fluxbox/startup

$ xrandr --output DVI-I-1 --mode 1920x1080 --pos 0x0 && xrandr --output VGA-1 --mode 1440x900 --pos 1920x0 &

The above does the same as the above xorg.conf configuration.