I just purchased Inspiron 9100 and building XP Pro + Slackware 9.1 double boot on it. It feels so comforting to see another person fighting with the same issues
My success so far:
- multiboot works: XP MBR booter, grub chained from boot.ini. Built-in support of USB storage and USB memory drive were extremely helpful

- WiFi works: ndiswrapper and stock Dell drivers that came with laptop (Dell R63259.exe) work out of the box.
- video somewhat works. I was able to install DRI drivers from dri.sourceforge.net and configure X to use full 1920x1200. Hardware acceleration doesn't work for now.
Download and install latest DRI drivers from dri.sourceforge.net. I used
r200-20040401-linux.i386.tar.bz2 from
h.t.t.p://www.freedesktop.org/~dri/snapshots/
and XFree86 from
h.t.t.p://www.freedesktop.org/~dri/snapshots/extras/XFree86.bz2
Below is my XF86Config-4. I think Most important sections are "Monitor" and "Device". Note that its work in progress and I'm a complete Linux newbee so chances are very good it may be improved in many ways
# **********************************************************************
# DRI Section
# **********************************************************************
Section "dri"
# Access to OpenGL ICD is allowed for all users:
Mode 0666
EndSection
# **********************************************************************
# Module section -- this section is used to specify
# which dynamically loadable modules to load.
# **********************************************************************
#
Section "Module"
Load "dbe" # Double buffer extension
# This loads the miscellaneous extensions module, and disables
# initialisation of the XFree86-DGA extension within that module.
SubSection "extmod"
# Option "omit xfree86-dga"
EndSubSection
Load "type1"
Load "freetype"
Load "glx" # libglx.a
Load "dri" # libdri.a
EndSection
# **********************************************************************
# Files section. This allows default font and rgb paths to be set
# **********************************************************************
Section "Files"
RgbPath "/usr/X11R6/lib/X11/rgb"
FontPath "/usr/X11R6/lib/X11/fonts/local/"
FontPath "/usr/X11R6/lib/X11/fonts/misc/"
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/Speedo/"
FontPath "/usr/X11R6/lib/X11/fonts/75dpi/"
FontPath "/usr/X11R6/lib/X11/fonts/100dpi/"
# ModulePath "/usr/X11R6/lib/modules"
EndSection
# **********************************************************************
# Server flags section.
# **********************************************************************
Section "ServerFlags"
EndSection
# **********************************************************************
# Input devices
# **********************************************************************
# **********************************************************************
# Core keyboard's InputDevice section
# **********************************************************************
Section "InputDevice"
Identifier "Keyboard1"
Driver "Keyboard"
Option "AutoRepeat" "500 30"
Option "XkbRules" "xfree86"
Option "XkbModel" "pc105"
Option "XkbLayout" "us"
EndSection
# **********************************************************************
# Core Pointer's InputDevice section
# **********************************************************************
Section "InputDevice"
Identifier "Mouse1"
Driver "mouse"
Option "Protocol" "ImPS/2"
Option "ZAxisMapping" "4 5"
Option "Device" "/dev/mouse"
EndSection
# **********************************************************************
# Monitor section
# **********************************************************************
Section "Monitor"
Identifier "Monitor0"
HorizSync 31.5 - 100
VertRefresh 50 - 90
Modeline "1920x1200" 246.59 1920 2064 2272 2624 1200 1201 1204 1253
Option "dpms"
EndSection
# **********************************************************************
# Graphics device section
# **********************************************************************
# === ATI device section ===
Section "Device"
Identifier "ATI Graphics Adapter"
Driver "radeon"
BusID "PCI:1:0:0" # vendor=1002, device=4e50
Screen 0
EndSection
# **********************************************************************
# Screen sections
# **********************************************************************
Section "Screen"
Identifier "Screen0"
Device "ATI Graphics Adapter"
Monitor "Monitor0"
DefaultDepth 24
#Option "backingstore"
Subsection "Display"
Depth 24
Modes "1920x1200" "1024x768" "1152x864" "1280x960" "1280x1024" "1400x1050"
ViewPort 0 0 # initial origin if mode is smaller than desktop
# Virtual 1280 1024
EndSubsection
EndSection
# **********************************************************************
# ServerLayout sections.
# **********************************************************************
Section "ServerLayout"
Identifier "Server Layout"
Screen "Screen0"
InputDevice "Mouse1" "CorePointer"
InputDevice "Keyboard1" "CoreKeyboard"
EndSection
### EOF ###