My Thinkpad X300 is a great machine and everything in Ubuntu 10.04 works natively except for scrolling with the TrackPoint. I’ve gotten it working but it never sticks after putting the laptop to sleep. Below are the instructions modified for a Thinkpad X300.
1. Install gpointing-device-settings
Open terminal and type sudo apt-get install gpointing-device-settings
2. Enable scrolling with TrackPoint
Open gpointing-device-settings and click DualPoint Stick and check use wheel emulation with button 2.
3. Create /usr/lib/X11/xorg.conf.d/20-thinkpad.conf
Section “InputClass”
Identifier “Trackpoint Wheel Emulation”
MatchProduct “DualPoint Stick”
MatchDevicePath “/dev/input/event*”
Driver “evdev”
Option “EmulateWheel” “true”
Option “EmulateWheelButton” “2”
Option “Emulate3Buttons” “false”
Option “XAxisMapping” “6 7”
Option “YAxisMapping” “4 5”
EndSection
I modified the instructions found here since they only partly worked for my X300.