It depends on who your battling.
go to the vally windworks trade for it or battle someone who has it
You can't. You have to trade from someone from Pokemon Diamond to get it. If you can trade from Diamond...
Trade with someone that has Pokemon pearl.
trade with someone that has Pokemon diamond
Trade in battle points at the battle frontier.
Trade a magmar with the magmarizer
Get it in a trade from someone else, or pal park.
you can trade with someone that has a dialga in pokemon diamond
I know you can them them to diamond/pearl/platinum but not to battle revolution :( But there is a way round this... You have to trade your Pokemon to diamond/pearl/platinum then you can copy to revolution :) And if you want you can trade back to soulsilver :)
same place
yes
What for? I already have one.