This mouse certainly is supported using IMPS/2. The following was generated automatically in RedHat 9:

(from /etc/X11/XF86Config)

Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "IMPS/2"
Option "Device" "/dev/input/mice"
Option "ZAxisMapping" "4 5"
Option "Emulate3Buttons" "no"
EndSection

Section "InputDevice"
# If the normal CorePointer mouse is not a USB mouse then
# this input device can be used in AlwaysCore mode to let you
# also use USB mice at the same time.
Identifier "DevInputMice"
Driver "mouse"
Option "Protocol" "IMPS/2"
Option "Device" "/dev/input/mice"
Option "ZAxisMapping" "4 5"
Option "Emulate3Buttons" "no"
EndSection


In gnome this makes the right side extra button also a right button, oddly enough. Scroll wheel works in mozilla. I haven't tried reconfiguring the buttons yet or trying PS/2 mode.

As far as the mouse goes: it's cheap, looks nice, feels and works nice. Can't beat that.

Didnt have to install the drivers, it works even better than it did on my windows machine

Besides the fact that its made by Microsoft, this is actually a very nice mouse. I recently found out that the two extra little side buttons that get mapped to other buttons in your DE (as a previous poster mentioned) can actually be mapped independently within Enemy Territory (and probably other FPS games as well). I now have the right side button mapped to command map, and the left side button to sprint :-). This mouse is cool; and by cool, I mean totally sweet.

Took a little work to get this one running, atleast with the side buttons functional. If protocol is set to IMPS/2 or auto, or anything like that, the side buttons were rendered useless (but the main 2 and scroll worked). In order to get it fully functional, I had to load it up as a Intellimouse Explorer (since essentially they are pretty much the same), with 7 buttons (4, plus middle click, and two for up and down on the scroll wheel). Next up I set the ZAxisMapping to be 6 and 7, so I could have my buttons listed in a logical order (Left is 1, middle is 2, right is 3, left side is 4, left right is 5, then the remaining two for scroll). Here's a copy of what I have in XF86Config-4

Section "InputDevice"
Identifier "PS/2 Mouse"
Driver "mouse"
Option "Protocol" "ExplorerPS/2"
Option "ZAxisMapping" "6 7"
Option "Device" "/dev/psaux"
Option "Emulate3Buttons" "true"
Option "Emulate3Timeout" "70"
Option "SendCoreEvents" "true"
Option "Buttons" "7"
EndSection

Next up, I mapped the buttons a bit differently (I have this in a script on loadup)

xmodmap -e "pointer = 1 2 3 6 7 4 5"
imwheel -k -b "67"

xmodmap remaps the buttons, because on default linux has the mouse wheel be 4 and 5 (you can probably set it that way in XF86config-4, so to skip part of this, but its just how I did it).

To get the wheel and the side buttons all working at the same time with the Mozilla Firefox 0.91 web browser and XFree86 4.3.0, without using imwheel:

XF86Config:
Section "InputDevice"
Identifier "Mouse1"
Driver "mouse"
Option "Device" "/dev/psaux"
Option "Protocol" "ExplorerPS/2"
Option "Emulate3Buttons" "no"
Option "Buttons" "7"
Option "ZAxisMapping" "6 7"
EndSection

make a $HOME/.Xmodmap before you log in, in the hope that
your X startup will take notice of it. The .Xmodmap file's contents should be one line:
pointer = 1 2 3 6 7 4 5

and/or run xmodmap -e "pointer = 1 2 3 6 7 4 5" in a shell window after you start X

Check that "xmodmap -pp" says this:

There are 7 pointer buttons defined.

Physical Button
Button Code
1 1
2 2
3 3
4 6
5 7
6 4
7 5

Check that you can see all the buttons when using "xev". The side buttons should be 6 (left side) and 7 and the wheel movement should look like buttons 4 (wheel up) and 5 are being pressed.

Then run Firefox. I didn't need to alter the about:config settings
from their defaults and after a quest of some years now, I have browsing nirvana... without needing imwheel any more.

PS. I'm using the mouse with the PS/2 adapter, not in USB mode.

Works great, the only thing I had to do to get all five buttons was add the line:

Options "Buttons" "5"

to the "Mouse1" section of /etc/X11/xorg.conf

Worked straight away. Wheel also works. Better than other distros I've tried anyway.