You need to have an event Arceus or an Arceus from pokemon Diamond, Pearl or Platinum and take it too the ruins of alph and there will be a guy who talks to you and you eventually end up in another set of ruins between sinnoh and Jhoto (Shinjho Ruins i think it's called) then you will choose what pokemon you want out of Dialga, Palkia or Girantina and you will receive an egg and that's it
i think you have to have Pokemon diamond to get him or her whatever.
At the spear pillar.
you dont
u can't
spear pillar at lv.47
You disappear and you reappear at the beach
Go to all the lakes after capturing diaga
stone pillar after beating Cyrus
no hes somewhere more secret
serebii.net has a lot of useful hints that can help you out if you need info on where to find Pokemon :)
Palkia, Water/Dragon which makes it only super effective against dragon. Its special move is Spacial Rend which does 100 damage and has a high chance of hitting a critical hit. Yea but diaga is better
no you can trade soulsilver pokemon to black