151: Manaphy - no way to catch it, go to the Pokemon mansion and read the book, this is the only way to see it w/o Pokemon ranger.152: Rotom - Go to the old chateau in enterna forest between 8:00 pm. and 6:00 am., and talk to a t.v.
both are legendaries.
sinnoh pokedex: manaphy, rotom national pokedex: don't have it yet
#151 in the sinnoh pokedex is rotom. you can find him at the old chateau at night in a TV. #152 in the sinnoh pokedex is manaphy. manaphy cannot be obtained directly in platinum, if I'm not mistaken. you'll need to play Pokemon ranger. #151 and 152 in the NATIONAL pokedex however, is mew and chikorita...
151 is Manphy 152 is rotom (catch it in the old house in the forest. at night talk to the TV)
151 manapy 152 rotom
In the Sinnoh Pokedex, 152 is Rotom, between Manaphy(151) and Gligar(153).
look on http://www.serebii.net/pokedex-dp/001.shtml
Rotom.
Pokemon Platinum has two different Pokedexes: the Sinnoh dex and the National Pokedex. In the Sinnoh dex, #152 is Rotom. In the National Pokedex, it's Chikorita.
Pokemon 152 is Chickoreta
In the sinnoh pokedex rotom is number 152 but in the national pokedex rotom is number 479 and chickorita is number 152
rotom
Picachu