On Route 222, the first fisherman has a magikarp and a gyarados. Magikarp is worth nothing for exp but the gyarados is worth 2k if your holding the exp share. I usually fight him with my Pokemon over and over until they are level 50. then I head for the 8th gym. After you defeat the 8th gym leader he will have 2 gyarados worth a total of 4k for killing 2 Pokemon in the battle. You should stay here til your Pokemon are level 60 then head to victory road.
Luxio evolves into Luxray exactly at level 30 on Pokemon platinum.
Then you have a level 70 pokemon!
obtained from the eighth gym leader or if you have a luxio don't let evolve until level 48 and then it will learn it. if you have let your luxio evolve (into luxray) then it will learn it at level 56. (platinum)
Giratina is level 47 in Platinum and level 70 in Diamond and Pearl
at level 34
Level 100
level 30
Level 934, that's the highest they go.
Arceus
train your Pokemon alot. i got all of my Pokemon to level 18 before the first gym because i trained them alot.
level 44
Level 10