You can go to the Move Deleter in Canalave City.
teach a flying Pokemon defog and use it
you can't!
There is no "Foggy city" in Pokemon Pearl it is a route celestic town you can use defog ( a hm when you beat the 4th ) to get rid of the fog.
You cant until you reach the Pokemon league
Use repel. You can buy one at the Pokemart (blue roof).
u cant if u want to get rid of a Pokemon just put it in a PC then click it if it says release press it and it will be gone if ur not getting rid of a Pokemon then u cant
Give it to your Pokemon (Not as an Item, use it by hitting the A button twice and choosing a Pokemon) or you can trash it (Hit A and hit the down button till you find trash and get rid of the amount you want to throw away).
No, it does not, because I copied my Pokemon from my Pearl version and my Pokemon were still there when I played it.
Yes. Go to Canalcave City and the move deleter will be in the second house to the left of the entrance.
You can delete HM Moves via the Move Deleter, who is located in Canalave City.
You need an HM to get rid of it. It's HM05 Defog, which you can get from the first guy on your right after you enter Pastoria City's Safari Park (The Great Marsh). Also, I think only Bird Pokemon can learn it.
you cant get a diamond on Pokemon pearl but you can get a pearl on diammond ...and pearl.