You have to go to Citadark Isle and go through it. At the end, you'll face Master Greevil (I think that's his name) and he has Shadow Zapdos, Moltres, Articuno, Lugia, Rhydon, Exeggutor and Tauros.
Yes.
moltres, arcticuno, and zapdos
Zapdos is only in firered, leafgreen, red, blue, yellow, green, xd gale of darkness.
Zapdos is not available in Emerald you will need to trade one from Firered, Leafgreen, or Pokemon XD Gale of Darkness.
at levl 30
If ever you mess up catching a legendary Pokemon such as zapdos if you saved before that moment you can reset your game and try again and if you didn't the only way to get a zapdos is from another firered or leafgreen or Pokemon xd gale of darkness.
sorry dude i don't think there is a glitch for that on Pokemon XD gale of darkness:(
No, Pokemon XD Gale of Darkness takes place 10 years after Pokemon Colosseum.
No, there is not a breeding center in Pokemon XD, Gale of Darkness.
Eggs cannot be obtained or given to Pokemon XD Gale of Darkness.
Pokemon XD (XD: Gale of Darkness) is for the Nintendo Gamecube.
Gligar will not evolve in xd gale of darkness.