Most of the multi-touch gestures available to iPhone and Apple laptop owners don't require anything special, hardware-wise—except a patent licence from Apple. Linux users, however, can get some of that multi-finger goodness in three quick steps.
The Ubuntu Snippets blog posts a configuration file, along with the copy-and-paste terminal commands needed to install and activate it, that give Linux users a rough approximation of some pretty great multi-touch features: two-finger vertical and horizontal scrolling, two- and three-finger tapping for middle- and right-clicks, respectively. As the author notes, three-finger tapping for a right-click is kind of hit-and-miss, and many users may not want any kind of tap-to-click powers at all. Luckily, it's easy to remove the last line or two from the config file posted to disable it—or, in systems like Ubuntu, simply disable tap-to-click from the Mouse configuration.
The file and steps were written for a system running Ubuntu 8.10 with a standard Synaptics touchpad, but would likely work for other modern Linux distributions. If you're not seeing any action, check to see where your hal systems keep their home in your distribution. Photo by franchesca_rauchi.
Multi touch for any,all synaptics touchpad [ubuntu snippets]