Regigas Help!

No. All you have to do is transfer all 3 regis from Ruby, Saphire or Emerald and go to Snowpoint Temple

Not exactly. You could also transfer the 3 Regis from R/S/E to Platinum using the Pal Park. Then going to Snowpoint Temple to get Regigigas.

The above reasons work, but if you want to unlock the 3 Regi areas in Platinum you'll have to have the Toys 'R Us Regigigas.

There is another way besides migrating if a friend of yours has a regigigas just borrow it from him and go catch regice,regirock and registeel (regigigas has to be in you're party) somewhere in mount coronet you can catch regice go to iron island and you should find registeel somewhere at the end of the cave and for regirock go to the resort area where there is a sandstorm you should find him there regice,regirock and registeel are at level 30 after you caught them go to snowpoint city and go to that temple where a woman is standing you need a national pokedex to enter the temple but you need regice,regirock,and registeel to catch regigigas.regigigas is level 1 when he's at the temple so bring a level 2 starly. I did that to it works 100 rate this comment make sure you give you're friend his regigigas back

Nope, not at all!!! I cheated, to be honest.

Use the Pokemon modifier code (it's long, but definetly worth it) and use the NATIONAL POKEDEX (put the national number in you calculator app, and run through grass while holding L) number to catch the three other Regis. After you catch them, put them in your party and go to the Snowpoint Temple, press A at the statue, and battle him.

He's level one, so he should be simple to catch. (at least in Platinum he is. I didn't catch in Diamond or Pearl)