Builders of the world's largest Tesla Coils, as well as various other High Voltage and High Energy devices.
http://www.lod.org/index.html
An extensive list of programs to calculate the various parameters of a Tesla Coil
http://hot-streamer.com/TeslaCoils/Programs/Programs.htm
Tesla Coils and the failure of lumped-element circuit theory. A very scholarly treatment of the subject.
http://www.ttr.com/corum/index.htm
How to make those discharge terminals by metal spinning on a lathe.
http://www.coe.ufrj.br/~acmq/spinning/
Plans, diagrams, pictures, movies and full descriptions of this super-efficient Twin Tesla Coil system, powered by a 360 Watt transformer
http://www.powerlabs.org/coil2.htm
Some very inteesting designs, and modiications to VTTC's.
http://chaoticuniverse.com/webdoc2.htg/Tubez.htm
Several hundred sites about Tesla Coils, construction, safety, hints, materials, and theory.
http://J.webring.com/hub?ring=teslaring
The Arcstarter Page. A journey through building a coil, well documented.This is about some older coils, but classics.
http://www.geocities.com/CapeCanaveral/Hangar/6160/tesla/tesla.html