Absolute Fretboard Trainer: Play-along course for mastering the fretboard of guitar, bass, mandolin.
ChordWizard: [Win] For guitar, banjo, mandolin, bass, ukulele, bouzouki, and others. Also offers free music theory tutorial.
Desktop Banjo: [Win] 5-string banjo learning tool that generates tablature and chords.
Desktop Music: Software for guitar, bass, and banjo players.
Funkyseagull.com: [Win - Mac] CD-ROMs for banjo, fiddle and guitar.
In-Tune Multi-Instrument Tuner: For tuning guitar, bass, banjo, mandolin, violin, viola, and cello. Other instruments via the pitch selector.
ScaleTool: Scale generator for guitar and piano.
The Violin Tutor: Teaches scales, arpeggios, exercises, at different tempos. Theory overview and finger patterns. Windows.
The Virtual Virtuoso: Accompaniment music plays to aid in the practice of scales, etudes, and performance pieces for violin, viola or cello.
Twofold Media: [Win] Description of Violin Magic Made Easy, a CD-Rom for the beginner violinist and support crew.
Virtual Fretboard: Guitar, tenor guitar, bass, and mandolin fretboards showing chords and scales.