what is the different??

what is the different between pokemon heart gold or pokemon soul silver, with pokemon platinum??

Different special Pokemon that can be obtain depends on the version.

Replying to #2

what is the special pokemon in pokemon heartgold and soul silver??

ho-oh and lugia?

Replying to #4

only that???
doesn't it the legendary pokemon from fire red??

fire red? i didnt saw lugia or ho-oh there instead i saw articuno zapdos and moltres

Well each version has their own set of pokemon HeartGold has Mankey/Primeape, Growlithe/Arcanine, Spinarak/Ariados, Gligar/Gliscor, Mantyke/Mantine, Phanpy/Donphan, Sableye, Baltoy/Claydol and Kyogre exclusives. While SoulSilver has Vulpix/Ninetales, Meowth/Persian, Ledyba/Ledian, Teddiursa/Ursaring, Delibird, Skarmory, Mawile, Gulpin/Swalot and Groudon as exclusive pokemon.And check here if you want to see.
http://bulbapedia.bulbagarden.net/wiki/Heart_Gold#Pok.C3.A9mon

bhatooth · #6fire red? i didnt saw lugia or ho-oh there instead i saw articuno zapdos and moltres

maybe not fire red..., i think you need a ticket to go to 9 island..