Sheet Music—Sources on the Internet
This web site gives lyrics and guitar chords for several current popular songs.
Hymns and Carols for Christmas:
IMSLP / Petrucci Music Library (International Library Score Library Project)
This website has mostly sheet music of older scores that are out of copyright. All scores may be downloaded at no charge. This source has a lot of classical music.
Levy Sheet Music Collection – Johns Hopkins University
This web site has the sheet music for older popular songs. Most of this collection is popular music from 1900-1930. The age of the music is a limiting factor for the web site, but it is an exciting web site because the music is actually online.
This web site has the lyrics for several folk songs. These folk songs are mainly traditional, but some newer ones are in this collection.
National Library of Australia
When searching under “all formats” choose “online” for online music.
This is also a web site with sheet music online. Again the music is older but if you are looking for the music to a classical piece this is probably a good web site to find it.