To get your scroll wheel to work, look in your /etc/X11/XF86Config file for a section that looks similar to this....
(In Mandrake, it may be in /etc/X11/XF86Config-4)
The important part is the Protocol, ZAxisMapping, and Buttons line.
If you have a mouse with buttons on the side for forward and back in a browser, set Buttons to 7. If you don't have those buttons, set Buttons to 5.
# The available mouse protocols types that you can set below are:
# Auto BusMouse GlidePoint GlidePointPS/2 IntelliMouse IMPS/2
# Logitech Microsoft MMHitTab MMSeries Mouseman MouseManPlusPS/2
# MouseSystems NetMousePS/2 NetScrollPS/2 OSMouse PS/2 SysMouse
# ThinkingMouse ThinkingMousePS/2 Xqueue
Option "Protocol" "IMPS/2"
# The mouse device. The device is normally set to /dev/mouse,
# which is usually a symbolic link to the real device.
Option "Device" "/dev/mouse"
Option "ZAxisMapping" "4 5"
Option "Buttons" "7"