EFi-X is another commercial product which allows a user to run Mac OS X on certain PC configurations, but unlike Psystar, which sells entire systems which require modifications to updates and such as not to render Mac OS X when Apple releases updates, EFi-X allows you to update your system with no issues.
The unit comprises of a USB module that when plugged into a USB port allows supported hardware to boot and install from an official un-modified Leopard DVD, Gizmodo have stated that even Mac OS X 10.5.5 from earlier this week can be installed without issue.
It is being pitched as a tool for enthusiasts rather than the general public trying to get a Mac for pennies, the unit retails at $155.00