you get it from a gy
flash isn't a HM but a TM and you can purchase it at goldenrod city super store thing
In Pokémon HeartGold, you can find the Rock Smash HM in Route 36, a fat guy will give it to you.yes. but flash in no longer an HM
its not an HM anymore you have to find it.
you get the HM Flash after beating the electric gym leader, if i recall correctly
There is no HM Dive in either Pokemon Silver/Gold or Heartgold/SoulSilver. It is exclusive to the Hoenn games.
Get all 16 badges and Oak will give it to you.
youy will need flash, all hm's, and rock smash. all the rest you might find useful in battle such as rest, toxic, and thunder.
You find the HM for Flash in Granite Cave in Dewford, talk to that person by the entrance and he gives you it.
You can't get rid of HMs in heartgold.
After beating blue, the 16th gym leader
you will find it on the ground but there is an ice puzzle to get it.
SORRY DUDE THERis no hm for whirlpool in pokemon pearl diamond or platinum only heartgold and soulsilver. but that wuld be AWESOME:))