hidden power
in the cave!
you have to bring arceus to the unown house
Nothing happens if the unown you catch can be arranged to spell water.
nothng happens
To be able to find more unown!
Unown can't learn other moves besides Hidden Power.
in Pokemon heartgold ruins of alph in Pokemon soulsilver ruins of alph
Nothing but Hidden Power.
Yes if you complete a puzzle in one of the buidings you go underground you can find UNOWN and capture them and if you speak to one of the people aboveground they will give you an UNOWN Report to regisster the types of UNOWN in.
The mysterious transmission in the ruins of alf are the UNOWN speakin to each other. Hope this helped.:)
In Pokemon gold/silver/crystal/heartgold/soulsilver you catch them at the Ruins Of Alph outsid violet! :D
In Summary, when you check moves, or in Battle, when you level up.