Guitar links

Annotated Guide to the Acoustic Guitar
Guild of American Luthiers

B-Band pickups
Darn good acoustic guitar pickups. Plug into heaven...
Funk Logic
Truly Essential Equipment
Just Strings
All kinds of strings for all kinds of instruments

Turbo Tuner
The best guitar tuner I have ever tried

Website of master guitar repairman Frank Ford

Guitar Builder's FAQ by Bill Wyza
Guitar Refinishing by Wm Lester
Guitar Setup 101 by luthier Charles Tauber
Guitar Shielding and Wiring (etc) by John Atchley

Suppliers (tools, parts etc):
Stewart Macdonald Guitar Shop Supply
Huge selection of specialised tools and supplies
(Where would I be without them...)
The Luthier's Mercantile
Tonewoods, tools, more
(Get the catalogue! Mucho info...)
Warmoth Guitar Products
The best a man (or woman) can get

Cool instruments:
Ukuleles by Kawika
Fine ukuleles from Hawaii, plus lots of very interesting information for luthiers
Lutes by Arthur Robb
Beautiful Renaissance instruments