According to the developer blog which initially told of the Atom incompatibility, the latest build of OS X 10.6.2 does retain support for Atom chips. It was previously reported that support for the Intel chip had been dropped, a move that many believed was Apple's attempt to stop the small but burgeoning "Hackintosh" netbook community. This all may change when the final 10.6.2 build is released, but as of now Atom support has returned.
Intel's Atom processor is a low-power, low-cost chip which is intended for notebooks and ultra-mobile PCs. No current Apple products use the chip, but a community has formed around installing Snow Leopard on so called "Hackintosh" netbook PCs which use the Atom processor. This unauthorized use of Apple's operating system has grown in popularity since the release of small, inexpensive notebooks such as the Dell Mini 10v, which allowed for easy installs of OS X.
Last year, it was reported that an executive at Intel had publicly vouched for the Atom processor to be used in Apple's tablet. With the buyout of chip designer P.A. Semi, many believe that Apple is instead designing its own chips for the platform.