LyricWiki.org is a terrific, free archive of song lyrics. How large? At the moment it has over 669,000 content pages. It's a broad and deep catalog. Search for Alanis Morissette and you'll see that she released three albums prior to her famous "Jagged Little Pill" in 1995. With such a useful database it's fortunate for developers and web site owners there's the LyricWiki API. This well documented SOAP-based API provides methods that enable programmed search, get, and post operations.
The LyricWiki API lets you search for songs, artists, and albums. You can get the lyrics for a specific song; get an artist's discography; or get a track listing for a specific album. You can also post new information into the LyricWiki archive: a new artist, an album, and song lyrics. The API exposes many of their site features like Song of the Day and Album of the Week.
If you've got a music-related site, and you'd like to provide your visitors with lyrics, applying the LyricWiki API will give you and your site visitors access to what may well be the largest lyrics archive on the Web.
For more music-related APIs and mashups check the ProgrammableWeb Music Dashboard.