Hi Barney - I am not sure that I can help.  The only Alkan sheet music I
have is an old Schirmers book edited by Raymond Lewenthal dating back to
64.  It is oprobably a collector's item by now, and is frequently referred
to in liner notes for CDs.  I understand that the publisher Beck and
Billaudot have published some of his works, or at least did at one time.
I don not know of anything available on the web, although I think I saw
something once, and will see if I can find out where.

The music library here at Flroida State University has several books
of Alkan works.  You might try the Library of Congress web site.  You
did not say what country you are in, but it shouldn't matter if you can
access these places online.  I am looking for the sheet music for the 2nd
Nocturne, which is one of my favorites.  I'll get back to you if I find any
more information.

Joel Hill
Tallahassee, FL - USA
ALKAN Web Page: http://www.nettally.com/joelhill/alkan