Tunes are in abc format.
For more about this extremely cool music notation visit Chris Walshaw's ABC home page .
Chris has lots of pointers to other online music collections, and a list of software sources.

Not ready to learn abc? Check out the Online abc Converter where abc notation
can be translated online to midi, JPEG and PDF sheet music.
I also recommend JC's ABC Tune Finder - an amazing search engine for tunes in abc format.

Original tunes by Sarah Gowan
Original tunes by Bill Quern

SPUDS Tune Links