Depends on whether or not you're in the Battle Frontier.
No
First you have to have wifi. If you do than you have to beat the game and go to the fight area. then go to the right for a while than go to the battle tower and chose battle using wifi.
by using wifi or wireless at a certain place
Pokewalker is the name of a round shaped pedometer that Pokemon fans can connect to either Pokemon HeartGold or SoulSilver. They can then use any Wifi setting to earn experience and points through the sources on the device.
Only if all your Pokemon in your party are legit
Using the WIFI link in Pokemon, it is possible to trade Pokemon with people around the world.
try using wifi
You cannot.
By using WiFi or IR or in-game trades, the list goes on and on
You can't get WiFi in a Pokemon game on a PC.
Well, currently no roms or emulators will have any wifi on them, so you have to wait a while until a new emulator comes out that can use wifi.
Using WiFi you can trade w/ others online.