Here are some links that I found very useful while researching Tesla coils and other High-voltage devices:

Sam Barros' POWERLABS	http://www.powerlabs.org
Chuck Hobson's Site	http://www.charles.a.hobson.btinternet.co.uk/
Mike's Electric Stuff	http://www.electricstuff.co.uk
Tesla Coil Mailing Ring	http://www.pupman.com
Alan Sharp's Homepage	http://ourworld.compuserve.com/homepages/alansharp/
Dr Duncan Cadd's Page	http://home.freeuk.net/dunckx
Nick Field's Page	http://www.tesla-coil.co.uk
Terry Fritz's Page	http://www.hot-streamer.com
The Tesla Webring	http://nav.webring.yahoo.com/hub?ring=TeslaRing&id=226&next
Steve Rodway	http://www.tcbouk.org.uk (Tesla Coil Builders of the UK)
	http://www.legion-elec.demon.co.uk (Legion Electronics)
Nick Field	http://www.tesla-coil.co.uk
Mike Tucknott's Page	http://freespace.virgin.net/michael.tucknott/

I will be adding to this all the time - WATCH THIS SPACE