English guy on gamefaqs summarise for me,
my language very bad! sorry -
- New images for Kanto/Johto Pokemon, DPP images for Hoenn/Sinnoh Pokemon.
- New PokeGear with phone, radio and new apps. DSi-exclusive camera app you save image to dsi memorys. Gold-Silver versions, you can change at Silph Co. It's backwards compatible with Poketch apps (!).
- New DSi app: Pokebox. It's a mini-Pokemon Ranch.
- Little changes on the story and some gameplay differences. Bug catching, fishing. Sweet honey replaces headbutt.
- Ho-Oh, Lugia, and the three dogs, just like in the original games.
- Kanto is available, you can obtain Kanto starters, Mewtwo and the birds. Safari Zone and Cinnabar Island are present.
- Secret islands and locations for event pokemons: Mew, Deoxys. GS Celebi event is back, though maybe it'll be removed from non-japanese versions...
- Underground, secret bases, fossils, gems. You can obtain the fossil pokemons at Cinnabar Island.
- Battle Frontier. After you finish it, you can obtain a Hoenn starter.
Worth to note there no new pokemon but all pokemon so far available
and you see but not catch red gyarados this one!
Just saying, stuff isn't real until you see it on serebii.net, Pokemon Sunday, SPPf's Confirmed Info Topic, or Pokemon.com.jp