http://geofex.com/Article_Folders/TStech/tsxfram.htm
http://sound.westhost.com/project64.htm
http://sound.westhost.com/project49.htm
standard equalizer plus bonus distortion unit
http://www.sound.au.com/project64.htm
Guitar amplification is a specialized field, where much commonly understood theory does not apply, and little theory is published. Technically speaking, a guitar amplifier has a specific type of non-linear gain at its signal extremes, and a specialized type of limited frequency response. This article collection has lots of information on guitar amplifiers.
http://users.chariot.net.au/~gmarts/ampsmain.htm
The Tube Screamer series of distortion/overdrive boxes from Ibanez has a reputation that has led them to pass into musical urban myth. Helped along with Stevie Ray's use of them, the TS 808 and TS 9 have been sought after and traded up to astronomical prices. All the members of the TS family share a common technical design, with the similarities vastly overwhelming the differences. This document describes the technologies used in them.
http://geofex.com/Article_Folders/TStech/tsxfram.htm
Wah, Fuzz and sustain circuits
http://members.shaw.ca/roma/wah.html
simple spring reverb unit
http://www.montagar.com/~patj/screverb.gif