Great Resources:
Mandolin Cafe a great place for forums, news, and classified listings
Jazz Mando - with a focus on Jazz
The Bluegrass Situation - the website for bluegrass and Americana music
Fretboard Journal - the premier print magazine for primarily guitar enthusiasts
Mandozine - resource site for the learning mandolin player
No Depression - a one-time print magazine, now an online journal on Americana music

Retail Stores:
The Mandolin Store - new and used instruments in Surprise, Arizona - a dealer for Gibson, Eastman, Weber, Lafferty, and others
Elderly Instruments - new and used instruments and all the accessories you'll ever need in Lansing, Michigan
Mandomutt - a small, but choice, selection of mostly used mandolins and guitars in Efland, North Carolina
Fiddler's Green Music Shop - an acoustic music store in Austin, Texas - dealer for Collings, Ellis, Pava, and more
The Music Emporium - new and used instruments in Lexington, Massachusetts
Greg Boyd's House of Fine Instruments - new and used instruments in Missoula, Montana
Gruhn Guitars - new and used instruments in Nashville, Tennessee
Carter Vintage Guitars - new and used high-end instruments in Nashville, Tennessee - a Gilchrist, Duff, Altman, and Pava dealer
Acoustic Music Works - new and used instruments in Pittsburgh, Pennsylvania - a Collings, Stiver, and Phoenix dealer

Music Festivals:
Wintergrass - Bluegrass Festival in Bellevue, WA

Camps & Schools:
Monroe Mandolin Camp in Kingston Springs, TN
Steve Kaufman's Acoustic Kamp near Knoxville, TN