About Tab - Information on Wayne Cripps' TAB format
Avid - Sibelius Music notation
Desktop Music Handbook - Cakewalk info about midi
Fandango Lute tablature and notation editor and composer
MarmaladeFoo: Typeset tablature in Excel
MuseScore | Free music composition and notation software
Music Notation Software FORTE - Music Writing & Composition
MusicXML - music exchange format
PDFtoMusic Pro - Play back and save music pdfs to XML and other formats