Developer Luke Hutchison has devised a way to implement multitouch in a few of the major apps (Chrome and Maps) as well as a few demo applications. Thought the current build isn't as smooth as the iPhone or Pre multitouch zooming, with some dev help it easily could be—the solution lacks OpenGL acceleration for the time being, having just been released today. And even with the lack of hardware acceleration, performance is more than bearable.
Unfortunately this isn't the simplest of installs, as Hutchison's modifications are mostly at the kernel level. This means you have to flash your phone's firmware, which the developer politely describes as carrying a "non-zero risk" of bricking your phone or voiding your warranty. But this is all very new and fresh—with some time and refinement, Android multitouch could well be within the reach of you average user. [Luke Hutchison—Thanks, Ryan!]