Free Sheet Music
CLASSICAL
IMSLP.ORG - IMSLP is a FREE database consisting of classical sheet music (solo music, orchestral parts, full orchestra scores, and arrangements of solos for various instruments) and some recordings. This website is a VERY GOOD reference site!!! Pieces are public-domain. The easiest way to navigate the site would be to select "Browse by Composer" and then go from there (click on the alphabet links on the top of the page according to the name of the composer you are looking up).
"MAINSTREAM" and MUSICAL THEATRE
Includes "Pop", R&B, Country, Rock, Alternative, Rap, Indie, etc. (anything you will hear on a "hit" radio station).
"Pianolicious blogspot" - Pianolicious blogspot has a lot of free sheet music - they are mostly transcriptions of "pop" music from contributing musicians. You can also find Musical Theatre, Classical, and "easy-listening" sheets.
**Tip - If you cannot find the song you want on Pianolicious blogspot, then do a web search for the song and include the word "blogspot" in your search. Most current "pop" music tends to be downloaded to "blogspot" websites.
CHRISTIAN
Cantate Domino - Free sheet music and recordings. Choral-style music. Click on "Music Library" to access music.
Sally DeFord Music - Free sheet music and recordings.
NEW AGE / EASY-LISTENING
Jon Schmidt - Free sheet music listed on right-hand side of site. This is the composer's website.
New Age Piano - This site has free sheet music to download, along with sound samples of those pieces. Pieces are submitted by the composers.
Solo Sheets -Solos submitted by composer - most pieces are of "easy" level. You can listen to a sound recording of most of the pieces, but please note that some of the recordings are not performed 100% accurately.
Other Useful Links
Manuscript Paper - Free manuscript paper - be sure to use the adjusting tools to create the type of sheet music you would like (you can select which clefs to add on the right-side of the page and adjust the "scale" to add more or subtract staves from the paper - then print when you are done).
ONLINE METRONOME - Free online metronome.
MUSIC THEORY QUIZZES - Free music theory documents, plus free online theory quizzes.
PANDORA - Pandora Radio is a free online radio. You can create "stations" (any genre) and the radio will generate a "station" with similar artists/tracks.
Music Editor - Compose music on manuscript paper using this free online tool. I prefer to use Finale (see next link), however you have to download Finale.
Finale - Music composition software. You can download a FREE version of Finale called "Finale Workbook" - works GREAT! I realize that recently Finale does not offer this free version (or at least I cannot find it! - you might have luck finding it on download.cnet.com), however under the "Downloads" tab there is a "Free Trial" page where you can download the program and try it for 30 days.