[UPDATE] Das Jahr is no longer in the WIMA, (it is now available commercially) but there's a some other free music by Hensel in the Petrucci Library.
I regularly troll around the various on-line music libraries in search of this piece or that. Lately, or at least for the past two years I have been hoping for a PDF edition of Fanny Mendelssohn's (or Fanny Hensel's) Das Jahr to pop up, and I can barely contain my excitement that the music for Das Jahr is in the Werner Icking Music Archive. The very kind person who did the computer engraving began with the month of June, which is one of my all-time favorite 19th-century piano pieces. It even sounds remarkable in a midi. I'm sending links to it to all my favorite local pianists, and sharing this "gem sighting" here.