I've been curious about this also.

*watches thread*
Call me Wes.
Fender American Deluxe HSS Strat
Chicago Blues Box Roadhouse
Bad Cat Cougar 5
1957 Gibson GA-5
Ceriatone 18w TMB Combo
Hughes & Kettner Tube Factor
Various Ibanez TS9s
Weber MASS Attenuator
Entirely up to you. Experiment. Some people have the mic like an inch away, at the centre of the cone, others have it 6 inches away, slightly off centre.

Volume is as loud as you want it to get the tone you want, if you're using a preamp with the mic you can turn the gain down so the actual recording volume will be lower than what's coming out the amp.

Basically, just play around with it.
No man has the right to be an amateur in the matter of physical training. It is a shame for a man to grow old without seeing the beauty and strength of which his body is capable

The setup for an sm57, as described by the manual, toward the outside edge of the speaker cone, 6-10".
Yup a whole lot of trial and error.. Im finally making head way with my setup. And its all dependant of the rig and your setup as well so what works for one might not work for another.

Theres some cool videos that discuss the basics and techniques. Watch them then sit down infront of the rig, move, test, move and record everything you do and keep notes in relation to how it sounds.