Now, all 600+ works of the master is available to search and view online.
Here's what they say on their 'about' page:
The Internationale Stiftung Mozarteum (ISM) and The Packard Humanities Institute (PHI) have agreed to establish a comprehensive digital edition of the music of Mozart, with the goal of making all of Mozart's music in the form of digital scores and parts freely available to the broadest public, online and in other electronic formats, for study and performance. The intention is that there will not be any charge to the public for online access - including downloading for local printing, study and performance - and only a minimal handling charge for the data on CD ROM or similar media.
The new digital edition will serve several audiences, including editors, researchers and performers (both professional and amateur). It will not be identical in text and design with the printed volumes of the Neue Mozart-Ausgabe (NMA) of the ISM, but the contents of the new digital edition will be based on, and closely coordinated with, the authoritative NMA. The inheritant flexibility of the digital format will make it possible to incorporate alternate versions or interpretations, and to keep the edition up to date.
A new Mozart Institute of the ISM will be established in Salzburg with primary responsibility for the contents of this electronic edition. This will provide continuity with the existing NMA editorial function.
Within agreed guidelines, the digital edition will be controlled by a committee with representation from the ISM and PHI.
Be sure to go over and give this site a try!!