You can change your clothes for online, by talking to some guy on the second floor of one of the first pokecenters
Chat with our AI personalities
Yes, you can. Pokemon HeartGold uses the time from your DS settings. So, change the time on the DS and the time in Pokemon HeartGold will change with it.
Unfortunately, you can't change gears on bikes in HeartGold.
Pokémon HeartGold isn't out yet. And anyway you can't change language in a Pokémon game.
No. You can't change languages. Even in SoulSilver.
You have to change the time on your DS in settings.