Barbershop Is Awesome
Barbershop Harmony Society
The Barbershop Wiki Project - Fantastic information on quartets, choruses, and contests throughout history
The Harmonet Reporter - Definitive source of barbershop contest scores for choruses and quartets for all time
Barbershop Music Database - Quartet and chorus scores from more than 20 years of district and international contests. Find out how often a song has been sung at contest, by whom, and how they scored
Just Intonation - Details about how to tune each note in a chord for optimal ringing

Where To Get Music
Harmony Marketplace - Best resource for purchasing barbershop charts
BHS Free 'n Easy - Free music for printing - Great a capella arrangements by Jon Nicholas
RC Music - Vocal arrangements by Brian Beck, David Briner, Renee Craig, Greg Volk, and others that may not be found in Harmony Marketplace - Tom Gentry arrangements - Steve Tramack arrangements - David Harrington arrangements - Adam Scott arrangements - Sheet Music Plus has everything, if you can find it

Learning Track Resources
BHS - Who is making learning tracks? - Who else is out there?
Barbershop Tracks - The Learning Track Database
Barbershop Connections - Find arrangers, learning track producers, choruses, barbershop organizations, and more

Affiliated Organizations
The Kentuckians Chorus, Lexington, Kentucky
Southern Gateway Chorus, Cincinnati, Ohio
Kentucky Vocal Union, Elizabethtown, Kentucky
Saltaires Chorus, Salt Lake City, Utah
North Front Sound, Davis County, Utah chorus
K-Town Chorus, Kaysville, Utah youth chorus
The 4 Hims, Kaysville, Utah quartet

Technical Resources
Cincopa - Embedded media player
SoundCloud - Record, upload, and share sounds
Gumroad - Sell stuff