Set Up Dual Monitors - xorg.conf - HOW-TOS

Get a computer
Get two monitors
Drink Bawls (tm)
Install an operating system (preferrably not OS2/Warp or BeOS - try something *nix)
Install X
Run the auto xorg.conf generator (dexconf, usually)

Edit your xorg.conf file

Add another display Device

Section "Device"
    Identifier  "radeon0"
    Driver      "ati"
    BusID       "PCI:1:0:0"
    Screen 0
EndSection

Section "Device"
    Identifier  "radeon1"
    Driver      "ati"
    BusID       "PCI:1:0:0"
    Screen 1
EndSection

Add another Monitor

Section "Monitor"
    Identifier  "monitor0"
    Option      "DPMS"
EndSection

Section "Monitor"
    Identifier  "monitor1"
    Option      "DPMS"
EndSection

Add another Screen

Section "Screen"
    Identifier  "screen0"
    Device      "radeon0"
    Monitor     "monitor0"
    DefaultDepth    24
    SubSection "Display"
        Depth       1
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
    SubSection "Display"
        Depth       4
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
    SubSection "Display"
        Depth       8
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
    SubSection "Display"
        Depth       15
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
    SubSection "Display"
        Depth       16
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
    SubSection "Display"
        Depth       24
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
EndSection

Section "Screen"
    Identifier  "screen1"
    Device      "radeon1"
    Monitor     "monitor1"
    DefaultDepth    24
    SubSection "Display"
        Depth       1
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
    SubSection "Display"
        Depth       4
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
    SubSection "Display"
        Depth       8
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
    SubSection "Display"
        Depth       15
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
    SubSection "Display"
        Depth       16
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
    SubSection "Display"
        Depth       24
        Modes       "1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
    EndSubSection
EndSection

Pull it all together in your ServerLayout block

Section "ServerLayout"
    Identifier  "Default Layout"
    Screen      "screen0"
    Screen      "screen1" RightOf "screen0"
    InputDevice "Generic Keyboard"
    InputDevice "Configured Mouse"

    # Don't forget xinerama!!!111oneoneone11!eleven!!11
    Option "xinerama" "on"
    Option "clone" "off"
EndSection

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