Int'l Laws of War (was Re: BULLSHIT)

If you prefer your info in book format, there's an excellent volume called
"The Laws of War: a comprehensive collection of primary documents on
international laws governing armed conflict"

Compiled by W. Michael Reisman and Chris T. Antoniou; ISBN 067973712X.

Gives much the same information as the ICRC website John cited, but you won't
go crosseyed hacking through legalese on a computer screen!

The Red Cross runs an excellent website, though.