700 volts? Yeowch!

I just got a used Fender Blues DeVille 2x12, and am reading up on some tube safety. I know the fragility and stuff of tubes, but I want to know moer about the lethal voltages. I usually tinker with equipment, sometimes only just taking off teh back panels and looking, so I want to know what NOT to touch. I read the tube amps can carry lethal voltages even after its unplugged, so right now im pretty much scared to just touch my amp Can anybody tell me what is safe to touch and what to avoid, or direct me to some good websites? All I can find is general information.

Fender Special Edition Koa Strat
Epiphone Les Paul Classic
Visual Sound Jeckyll & Hyde Overdrive
Fender Blues DeVille 2x12