When you're walking to Snowpoint City you walk through Route 217. In the last bit when you're just about to get out of the open there is a house on the left side. Behind it there is a item in the shape of a poke ball. Take that, and that's rock climb. Also, if after you get it go into the house and talk to the guy. You'll get a reward, though I forget what it is.
If you go to this URL, then it's a map of Route 217. The house that's marked "1" is the house I described. The red line pointing to something behind it is the HM Rock Climb
URL: http://archives.bulbagarden.net/media/upload/thumb/6/62/Route217.png/300px-Route217.png
Hope this helps!
get all 16 badges
Some are rhydon, golem, and golduck.
you go to roky places up hills
Okay: 1:It's PLATINUM not PLATNOM. 2:It's a Pokemon game that's an upgraded version of Pokemon pearl and diamond.
migrate it from firered, or leafgreen
online? no
you don't
In Pokemon platnom the door opens magically when you catch the newest Pokemon CROWLEY caught at an event and when you go tho the door it should be open.
march 22
you need to have the national pokedex
Migrate one from leafgreen.
to get regirock in Pokemon platinum, you have to upload it from ruby, Sapphire, or emerald.