In Mauville city but only land form
you can get a shaymin in the Mauville city gym
No it didn't exist in Pokemon indigo.
No, and there is no game that is named "Pokémon Indigo."
Go to the Mauville City Gym.
It isn't the evolved form of shaymin it is the same Pokemon. To get it you trade your ordinary land form shaymin to Pokemon platinum and it changes into sky form. Only problem is Pokemon platinum dosent come out in England until next December. Hope this helps.
Shaymin cannot be found in Soul Silver.
Entei can be found in Nimbasa City in Pokemon Indigo.
You find shaymin in the flower of paradise. once you get there shaymin will be at level 30. good luck
Shaymin and Arceus are the only two Pokemon you cannot find or recruit. You can find every Pokemon from Bulbasaur to Darkrai, but not those two.
Yes, there is every Pokemon on Indigo. The easiest way to find Pokemon is to go to the ROOMS.
I doubt you will find Giratina on Pokemon indigo as it is not a generation 1 Pokemon (it isn't one of the first 151 Pokemon species)
The only way to obtain a Shaymin is to have someone trade it to you.