From Native Instruments....

KONTAKT 2 demo version online
KONTAKT 2 demo versions for Mac OS X and Win XP are
now online. Download the free trial version and
witness KONTAKT 2's unparalleled power and
versatility. Included with the demo is a library with
several demo instruments that make use of the new
functions, such as the convolution effect, KONTAKT
Script Processor, the surround panner and much more.
-> http://www.native-instruments.com/nlk2demo.info