SING virtualisation software, someone from Hungary illustrates how Mac OS X, Linux, and Windows can be worked on simultaneously (view screenshot and further details), without the need to boot into a different, independent partition.
This comes only a week or so after Boot Camp from Apple began supporing Linux. It now caters for Linux boots, as well as Windows boots. It relies on the availability of Intel chips, which replaced Power PC in an important strategic move. This makes the prediction and vision of triple-boot machines a reality, but moreover, it does so without the obvious perils. It obviates the need to reboot Mac OS X. This equips Apple with a huge selling point.