http://www.serebii.net/pokedex-rs/water.shtml
you can't get the black flute in leaf green but you can in Pokemon ruby, sapphire and emerald then trade it to leaf green.
It is in the wild, anywhere. Whenever you change location (go into houses, etc) it will change place. You need to 'unlock' it before you can get it though.
No, ruby does not dissolve in water. Rubies are composed mainly of aluminum oxide, which is not soluble in water.
first you have to own at least 60 pkmn, get pokedex from prof. oak,then talk to him; he will tell u to get ruby. fight team rocket and return to him.
your starter pokemon can be a water type and you can trade water type pokemon with your friends in pokemon ruby
water!
From the lake
You can find water on almost every route in Pokemon Ruby. Are you looking for a specific body of water? If so, I can't help you unless you ask for a specific body of water.
in grass close by water and in in water and while fishing
Well, darling, a ruby is denser than water, so unless you've got some magical ruby that defies the laws of physics, it's going to sink faster than my ex's excuses. So, no, a ruby won't be doing any synchronized swimming in your water glass anytime soon.
kyogre. OBVIOUSLY.
In the grass, caves and water