HP Driver Unlocks Multi-Touch On Older Touchpad
Although it was thought that older touchpads were not capable of multi-touch, this driver update appears to prove otherwise. Another pleasant surprise is the unlocking of two- and three-finger gestures since even modded drivers were not able to achieve this.
The drivers actually come from HP, but they will likely work on other laptops with Synaptics touchpads as well. There are drivers available for Windows XP, Vista, and 7.