If you own a laptop with Synaptics Touchpad, the right driver can make use of lots of nice features (e.g. horizontal, vertical and even circular scrolling).

To enable SHMConfig, create the file /etc/hal/fdi/policy/shmconfig.fdi containing following lines:

<?xml version="1.0" encoding="ISO-8859-1"?>
<deviceinfo version="0.2">
 <device>
  <match key="input.x11_driver" string="synaptics">
   <merge key="input.x11_options.SHMConfig" type="string">True</merge>
  </match>
 </device>
</deviceinfo>

/usr/share/X11/xorg.conf.d/20-thinkpad.conf

Section "InputClass"
Identifier "Trackpoint Wheel Emulation"
MatchProduct "TPPS/2 IBM TrackPoint|DualPoint Stick|Synaptics Inc. Composite TouchPad / TrackPoint"
MatchDevicePath "/dev/input/event*"
Option "EmulateWheel" "true"
Option "EmulateWheelButton" "2"
Option "Emulate3Buttons" "true"
Option "ZAxisMapping" "4 5"
EndSection

For further configuration install Gsynaptics, it provides e.g. circular scrolling (engage scrolling and move finger (counter-)clockwise, to scroll until battery runs out of power)

sudo apt-get install gsynaptics

After installation Gsynaptics can be accessed via System → Einstellungen (Settings?) → Touchpad.

http://wiki.archlinux.org/index.php/Touchpad_Synaptics_(Deutsch)

Section "InputDevice"
  Identifier      "Synaptics Touchpad"
  Driver          "synaptics"
  Option          "SendCoreEvents"    "true"
  Option          "Device"            "/dev/psaux"
  Option          "Protocol"          "auto-dev"
  Option          "HorizEdgeScroll"   "true"
  Option          "HorizScrollDelta"  "100"
  Option          "CircularScrolling" "on"
  Option          "CircScrollTrigger" "8"
  Option          "SHMConfig"         "true"
EndSection

SHMConfig has to be enabled. The following commands should be typed in a terminal.

The -d option causes syndaemon to run in the background, so the terminal can be closed after executing the command.

syndaemon -d

The -t option causes syndaemon to only disable tapping and scrolling, not mouse movements:

syndaemon -d -t

By default syndaemon disables the touchpad for 2 seconds after the last keyboard activity. To specify a different timeout, use the -i option. For example, a timeout of 1 second:

syndaemon -d -i 1