What type of tunes? John Chambers' (http://trillian.mit.edu/~jc/music/abc/findtune.html) may find them.

If it's songs, it becomes harder. Our site http://www.folkinfo.org/default.asp is a rare example of a site that tries to take advantage of the w: of abc to produce things like folk songs as graphics with underlined words, etc. but we are still in our first year and are only working on traditional songs.

Jon