Ok, I installed that ati drives and got xinerama to work with them but i have not 3D acceleration.

here is my xorg.conf. Any help is welcomed

# /.../
# SaX generated X11 config file
# Created on: 2006-09-10T02:42:24-0400.
#
# Version: 7.1
# Contact: Marcus Schaefer <sax@suse.de>, 2005
# Contact: SaX-User list <https://lists.berlios.de/mailman/listinfo/sax-users>
#
# Automatically generated by [ISaX] (7.1)
# PLEASE DO NOT EDIT THIS FILE!
#

Section "Files"
FontPath "/usr/X11R6/lib/X11/fonts/misc:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/local"
FontPath "/usr/X11R6/lib/X11/fonts/75dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/100dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/Type1"
FontPath "/usr/X11R6/lib/X11/fonts/URW"
FontPath "/usr/X11R6/lib/X11/fonts/Speedo"
FontPath "/usr/X11R6/lib/X11/fonts/PEX"
FontPath "/usr/X11R6/lib/X11/fonts/cyrillic"
FontPath "/usr/X11R6/lib/X11/fonts/latin2/misc:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/latin2/75dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/latin2/100dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/latin2/Type1"
FontPath "/usr/X11R6/lib/X11/fonts/latin7/75dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/baekmuk:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/japanese:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/kwintv"
FontPath "/usr/X11R6/lib/X11/fonts/truetype"
FontPath "/usr/X11R6/lib/X11/fonts/uni:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/CID"
FontPath "/usr/X11R6/lib/X11/fonts/ucs/misc:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/ucs/75dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/ucs/100dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/hellas/misc:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/hellas/75dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/hellas/100dpi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/hellas/Type1"
FontPath "/usr/X11R6/lib/X11/fonts/misc/sgi:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/xtest"
FontPath "/opt/kde3/share/fonts"
InputDevices "/dev/gpmdata"
InputDevices "/dev/input/mice"
EndSection

Section "ServerFlags"
Option "AllowMouseOpenFail" "on"
EndSection

Section "Module"
Load "dri"
Load "glx"
Load "type1"
Load "extmod"
Load "dbe"
Load "freetype"
Load "v4l"
EndSection

Section "InputDevice"
Driver "kbd"
Identifier "Keyboard[0]"
Option "Protocol" "Standard"
Option "XkbLayout" "us"
Option "XkbModel" "pc104"
Option "XkbRules" "xfree86"
EndSection


Section "InputDevice"
Driver "mouse"
Identifier "Mouse[1]"
Option "Buttons" "12"
Option "Device" "/dev/input/mice"
Option "Name" "Logitech USB Receiver"
Option "Protocol" "explorerps/2"
Option "Vendor" "Sysp"
Option "ZAxisMapping" "4 5"
EndSection


Section "Monitor"
Option "CalcAlgorithm" "XServerPool"
DisplaySize 360 270
HorizSync 30-96
Identifier "Monitor[0]"
ModelName "NEC MULTISYNC 95"
Option "DPMS"
VendorName "NEC"
VertRefresh 43-160
UseModes "Modes[0]"
EndSection

Section "Monitor"
DisplaySize 305 230
HorizSync 0-0
Identifier "aticonfig-Monitor[1]"
VendorName "ATI"
VertRefresh 0-0
UseModes "Modes[1]"
EndSection


Section "Modes"
Identifier "Modes[0]"
EndSection

Section "Modes"
Identifier "Modes[1]"
EndSection


Section "Screen"
DefaultDepth 24
SubSection "Display"
Depth 15
Modes "1280x1024" "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
SubSection "Display"
Depth 16
Modes "1280x1024" "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes "1280x1024" "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
SubSection "Display"
Depth 8
Modes "1280x1024" "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
Device "Device[0]"
Identifier "Screen[0]"
Monitor "Monitor[0]"
EndSection

Section "Screen"
DefaultDepth 24
SubSection "Display"
Depth 15
Modes "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
SubSection "Display"
Depth 16
Modes "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
SubSection "Display"
Depth 8
Modes "1280x960" "1280x800" "1152x864" "1280x768" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
Device "aticonfig-Device[1]"
Identifier "aticonfig-Screen[1]"
Monitor "aticonfig-Monitor[1]"
EndSection


Section "Device"
BoardName "RV280 5964"
BusID "PCI:1:0:0"
Driver "fglrx"
Identifier "Device[0]"
Option "SaXDualHead"
Option "SaXDualMonitorVendor" "NEC"
Option "HSync2" "30-96"
Option "VRefresh2" "50-160"
Option "Mode2" "1280x960,1280x800,1152x864,1280x768,1024x768,1280x600,1024x600,800x600,768x576,640x480"
Option "SaXDualResolution" "1280x960"
Option "DesktopSetup" "Horizontal,Reverse"
Option "SaXDualOrientation" "RightOf"
Option "SaXDualMode" "Xinerama"
Option "ForceMonitors" "auto,crt1"
Option "SaXDualHSync" "30-96"
Option "SaXDualMonitorModel" "NEC MULTISYNC 95"
Option "SaXDualVSync" "50-160"
Screen 0
VendorName "ATI"
EndSection

Section "Device"
BusID "PCI:1:0:0"
Driver "fglrx"
Identifier "aticonfig-Device[1]"
Screen 1
EndSection


Section "ServerLayout"
Identifier "Layout[all]"
InputDevice "Keyboard[0]" "CoreKeyboard"
InputDevice "Mouse[1]" "CorePointer"
Option "Clone" "off"
Option "Xinerama" "on"
Screen "aticonfig-Screen[1]" RightOf "Screen[0]"
# Screen "aticonfig-Screen[1]" LeftOf "Screen[0]"
Screen "Screen[0]"
Screen "aticonfig-Screen[1]"
EndSection


Section "DRI"
Group "video"
Mode 0660
EndSection

Section "Extensions"
EndSection