go to the building beside the gts talk to everybody
you can not get it from Pokemon platinum you can trade in to diamond or pearl
It learns it at Lv61 in Platinum.
you can find a grip claw in 217 because there are sneasel that are holding grip claw
Route 244
get a razor claw and a sneasel and level up
On Victory Road's first floor
After you beat fantina at the gym in hearthome city she will give you the TM shadow claw.
If you want to get quick claw in D/P or Platinum you will have to get it from R/S/E and migrate a Pokemon holding it
In the low right corner of Route 24.
its gone u dont get another
Use a Pokemon with mean look, or use a Pokemon with a trap ability.
No wild Pokemon hold the item razor claw but you can find razor claw at Route 224, Victory Road and available to buy at the Battle Tower (D/P) -Clensen