After you get all three Reggies (Regice, Registeel and Regirock) there is not much else to do with them seeing as you most likely caught them on the pokemon sapphire/ruby/emerald game. For either Pokemon diamond, pearl or platinum you can trade the three reggies onto it and go to the sacred chamber place which is the town below the snowpoint city gym and with all three reggies in your inventory you can unlock an entrance which leads to Regigas (sorry if spelt wrong been a while since played) it is very powerful and is level 70.
nope cause all the other reggies will awake reggigas from his sleep.
Trade with Pal Park.
you can't you have to import them from Pokemon emerald
No.
reggigigas is in a temple and is guarded by three pillers.one is steel one is rock and one is ice.reggi rock,steel,and ice are caught by the temple master named Brandan.
The 3 reggies are not in platinum they are only in the hoenn region unless you use cheats.
yes
kyogre, groudon, raquaza, jarachi (I think), deoxys (I think), latios, latias, the three reggies (regigigas couldn't be caught) and some more. I think.
They are Dialga, Giratina, Darkrai, Cresselia, Azelf, Uxie, Mesprit, all four Reggies, and if you consider him one, Heatran.
Yes, you need all three. So dust off your copy of ruby/sapphire/emerald and get working.
Reggie wedgie,
yes Regies:use the Pokemon modifier cheat witch you can find on this site