DiscoFreq's Effects Database
Bart has gone above and beyond the call of duty cataloguing a comprehensive list of FX companies and pedals. There are also interviews, reviews, schematics, and God knows what else lurking there
DIY Stomboxes FAQ
Another link to diystomboxes, but this one deserves it’s own link. A fantasic FAQ section that links to many more detailed explanations
The Doc offers a huge range of pedal parts and useful knowledge. Makes ordering the right bits a breeze compared to the big boys. Reasonable prices, fair delivery and a speedy service. Cannot recommend enough.
A great UK based music website. Great classifieds and very helpful members.
Classic site, especially the classifieds section