It all depends on game freak if they still want to make new Pokemon games.
there is no region after sinnoh in Pokemon diamond and Pokemon pearl.
I think your talking about HeartGold/SoulSilver. In Pokemon HeartGold/SoulSilver you're not capable of going to the Sinnoh region, only Jhoto and Kanto are avaliable.
Platinum is going to come out for the DS, and it's still in the Sinnoh region, but the main legendary Pokemon is going to be Giratina.
Pokémon Number 151 in the Sinnoh Dex is Manaphy! you can get manaphys pokadex info by going to the Pokemon mansion, then go to the first door to the right and talk to the book on the table
The Isshu Region.
NO! Pokemon SoulSilver Version is the exact same thing as Pokemon Silver Version. Only all the Kanto, Johto, Hoenn, and Sinnoh region Pokemon are in there.
you should find every Pokemon in sinnoh. i going to find all the pokemons in the national dex ;)
By seeing all the Pokemon in sinnoh and going to rowen's lab.
you cant do this. sorry
by going all over sinnoh and by trade
No, you won't be able to acquire a Sinnoh Starter in Pokémon HeartGold and SoulSilver, you'll have to trade for any of the Sinnoh Starters.
Yes, you can, Once you've beaten the elite 4, seen all the Pokemon in the Sinnoh region, and unlocked the national dex. You then put the emerald game cartridge into the ds and go to the palpark (reached by going south of sandgem town) and get your Pokemon there in a minigame