Ridge Runner
Digital study recorders plus instruction videos for guitar, fiddle, mandolin, dobro, banjo and other instruments.
http://www.ridgerunner.com/

Dr. Horsehair Music Co.
Banjo recordings and instruction books by Bob Flesher in the modern-day clawhammer banjo or frailing style and the old-time minstrel banjo stroke style.
http://www.drhorsehair.com/

FretsOnly
Online catalog of various educational products for guitar, banjo, mandolin and violin.
http://www.fretsonly.com/

Gordon Stobbe's Fiddle Music
Fiddle books, tune books, CDs and cassettes, old-time and stringband music.
http://www.fiddlebooks.com/

Kenn Smith's Bass Lessons
It offers bass instruction by mail.
http://www.angelfire.com/ks/bass/

Bass Pro Tips
Instruction books and CD-Rom by bass player Sergio Mottura.
http://www.bassprotips.com/

Fedor Violin Method
Description and ordering information for this instructional package (books and CDs).
http://www.fedorviolinmethod.com/

Handbook for Cello Students
A book for cello students and teachers.
http://www.cellohandbook.com/

Ross Nickerson Music
Sells some Banjo books and CDs. Audio samples provided.
http://www.rossnickerson.com/

10aDay Stringwizards
Offering a set of videos for beginning orchestra players, such as violin, viola, cello, and bass.
http://www.stringwizards.com/

Video Progressions
Offers some videos for bass and guitar covering different styles and levels.
http://www.videoprogressions.com/

Music Theory
Online and downloadable theory lessons for guitar and bass players. Information about the annual subscription.
http://www.theorylessons.com/

The Stacy Phillips Dobro and Fiddle Page
Offering some instructional books and videos.
http://www.stacyphillips.com/

Banjo Teacher.com
Offering online lessons, videos, books, DVDs and accessories.
http://www.banjoteacher.com/

Andrew Pfaff: Mode Shapes for Bass
Offering this text for electric bass written by this instructor and performer in the NYC area.
http://www.andrewpfaff.com/

Slap It!
Sale of books and online lessons for playing and sight-reading slap style funk basslines on electric bass.
http://www.slapit.com/

Stephanie Curcio Publications
Specializing in repertoire and pedagogical materials for both pedal and lever harps. Includes owner's profile and sound clips.
http://www.harpmusicpublisher.com/