its on an island that opens after you beat the elite four. to get there just surf a litle east of pacifilog town stay at the top and youll find a path the the sky tower
Ruby & Sapphire Key
new mauville after you get a key from Wallace
You can unregister them but you can't remove them from your pack
there is no key. you need to use an ar, or maybe link to a friend I'm not positive. but if your question is what is behind the locked door, it's an event. it's really similar to a battle tower type of thing. no key though.
tanoby key? do you mean braille key? If so, it's in the one island tunnel where you get the ruby.
Watson the gym leader of mauvile city will give it to you.
You don't
When you catch Regirock, you'll get a key depending on which version of the game you are on. You can use that key to catch a second of the trio, but to get the third, you need someone else with the other version to give you the key.
Braille key. With each Pokemon Ruby, Sapphire, Emerald, FireRed and LeafGreen version, you should obtain a Braille Key in the box. This gives you the symbols and the letters they stand for - which are used in the game. If you do not have this, it is easy to find. Wikipedia gives a Braille key under the heading "Writting Braille". Pokemon only uses the alphabetic letters and the symbols for the full stop and the comma. http://en.wikipedia.org/wiki/Braille
It is the warehouse in veilstone city.
In pikachu's snatch
The key is hidden in the basement of Pokemon Mansion which is located on Cinnibar Island.