The second edition of The Grove Dictionary of American Music has just been published and is now available in the Music Library (ML 101 .U6 N48 2013). Some articles are already available in Oxford Music Online, and the remainder are soon to come.
The National Geographic Virtual Library brings together a complete archive of National Geographic magazine — every page of every issue — along with a cross-searchable collection of National Geographic books, maps, images and videos.
Naxos Music Library has teamed up with Sony Classical to make their entire catalog available via streaming audio. A few hundred titles have already been added, and the remaining thousands of albums will be added continuously as part of their daily updates.