Linkage
helpful info, cool folks, interesting stuff...

Parts

Armadillo Amp Works - Makers of fine amp cabinets.
Hoffman Amps - purveyer of many excellent parts and much helpful advice.
Mojo Musical Supply - 'Nother good place for parts.
Antique Electronics - More parts, Hammond transformers.
Magic Parts - Ruby tubes and other amp parts
New Sensor - EH tubes/products and more parts, including good Marshall trannys
Weber VST - Great guitar speakers, chassis, and lots more.
Mercury Magnetics - Most excellent trannys for Marshalls, Fenders, and more.
Marstran - Nice looking, vintage-style Marshall trannys
The Tube Store - Very good source for tubes.
Mouser Electronics - General electronics, good prices, fast delivery!
Apex Jr. - Wire, caps, and other cool stuff.
Small Bear Electronics - When you wanna get small, parts for F/X pedals.

Info

Ampage - The best info site for tube guitar amps
Plexi Palace - Forum for Marshall freaks.
The T-Wreck Page - fans, builders, and tweaker of Ken Fisher's Trainwreck amps.
The SLOclone Forums - Disciples of gain and Students of the Soldano way.
Schematic Heaven - great listing of schematics and layout for Fenders, Marshalls, and others.
The Blue Guitar - Many helpful schems and info
18watt.com - Home of the 18watt Marshall and other groovy low-wattage fans.
ax84.com - A great source for low-wattage amp designs.
GeneralGuitarGadgets.com - PC boards, layouts, and more for F/X pedals.
TonePad.com - More PC boards, layouts, and F/X pedal info.
RunoffGroove.com - another site for F/X pedal fans. Some very cool overdrives based on classic amp designs/tones.
Premier Guitar Magazine - a great mag for tonehounds and gear heads
The Gear Page - forum for gearheads and tonehounds
Dumble Forum - dedicated to the amps of the elusive Mr. D
DIY Stompboxes - Aron Nelson's site with much helpful info about the world of stompboxes/FX

Cool Stuff!

Wayne Guitars - Wayne Charvel and Michael Charvel build some of the slickest guitars around.
Amalfitano Pickups - Killer hand-made pickups from Houston, TX. I've got 'em in my Les Paul and I LOVE 'em!!
Austone Electronics - Badass hand-made effects from Austin, TX
Loop Master - Very cool pedals for FX loops, A/B switching and channel switching.
ToneFactor - Boutique FX pedals including the ThunderTweak Delay