It's not exactly a phone, but you can obtain a PokeGear from your mother when you show your new starter Pokemon from Prof. Elm.
hawzhin
he will be anwhere see him and you get his phone number when you talk to him
There is no best Pokemon on Pokemon HeartGold.
there is no Pokemon Mansion in Heartgold.
you get this one trainers phone# and he sometimes sends you some
After you defeat her, you will automatically register her in the Pokegear.
They are not in Pokemon HeartGold
No, you don't. You cannot face the Sinnoh Gym Leaders in HeartGold.
Get her phone number registered in pokemon then ring her if you would want to battle her again
yes and you can get his phone number and battle him more check youtube for how to get his number
where is the pokemon transfer lab in heartgold
There is no such thing as a Great Basin Gold in Pokemon Diamond, Pearl, Platinum, Heartgold or Soulsilver.