The Eric Zeisl Archive is located at the University of California at Los Angeles. The archives contain nearly all of Zeisl's music manuscripts, as well as a vast correspondence which has been indexed and computerized for research on-line. A complete list of works in the archive is also here.
This site has an extensive non-commercial archive of mp3 files of interviews and lectures. The mp3 archive includes the audio guide from the extensive 2005 Eric Zeisl exhibition (view catalogue) at the Jewish Museum of Vienna.