If you own an old laptop with Synaptics touchpad, you can enable multi-touch features just by updating your device driver!
Just use one of the following setup files supplied by HP:
Windows XP: sp47816.exe
Windows Vista/7: sp47815.exe
It works also on notebooks of different manifacturers, like my Dell Inspiron 640m and HP Compaq nx6110.
Should work for every device with this identifier:
ACPI\SYN1E18=”Synaptics PS/2 Port Touchpad”
Install the package, reboot you laptop and set your preferences in the control panel.