MacBook multi-touch trackpad support
The trackpad in the 2008 white plastic MacBook isn't capable of supporting multitouch gestures. As it's a hardware limitation -- meaning the trackpad hardware can't sense input from 3-4 separate fingers at once -- there aren't any hacks to get around the limitation.

One way to get full multitouch support would be to get a Magic Trackpad. They'll work with any bluetooth-enabled Mac running Mac OS X Snow Leopard v10.6.4 or later.