From publisher blurb:
The Live System is designed to be a more free-flowing, fast playing & looser interpretation of the Open Gaming system. It contains systems & rules that present a more flowing, less structured & modern updating of the system, stripping out unnecessary complication & updating with standard innovations, such as the removal of levels.
The Live System is faster & deadlier but is more suited to both cinematic style games & to harder settings such as hard science fiction or gritty modern-day adventures.
The Live System may also be used to play standard 3rd & 3.5 edition games with a little conversion work & this SRD should contain enough information for you to be able to do so with little problem.