Where and how do you get these pokemon?

You can get a tyranitar from getting a larvitar or pupitar and you will find a larvitar on the islands you go to when your at blakes gym or on island 7.

Jirachi-Use the bonus disk that comes with Pokemon coliseum.

Rayquaza-Sky Piller.

Metagross-You need a Baltoy,"I think thas how you spell it"

Mightyena-Catch a mightyna and Evolve it,or Trade from another game.

Manectric-Same as it says for the above question^.

Tyranitar-Evovle it from a Lavatiar.

Jiarchi-the Pokemon bonus disk, Trade with a friend, or action replay
Rayquaza-(in Ruby or Sapphire or Emerald only)get after you beat the Elite Four, in sky pillar northeast of pacificinglog town
Metagross- (in Ruby or Sapphire or Emerald only)get the first form at stevens house after you beat the Elite Four
Mightyena-(in Ruby or Sapphire or Emerald only)Evolve a poocheyena, found in the routes at the beggining of the game
Manectirc- (in Ruby or Sapphire or Emerald only)Evolve an electirike, found the route north of slateport city
Tyranitar- get the first form in the Celadon City Game Corner, prize I think somewhere in the 4,000s, but I'm not sure, look for lavitar in the prize area

1. Cheats.
2. Sky Pillar on Emerald.
3. Evolve from Beldum. From Emerald you get him from Steven later.
4. Again, Emerald. Evolve from Poochyena.
5. Emerald again. Evolve from Electrike.
6. Southern feilds of 7 Island. Evolves from Larvitar.

~SGX

I all ready answer your question dude,you don't need to ask it again.

Jirachi can be obtained in nintendo event bonus disc or action replay or any cheating device
Rayquaza can be obtained in Sky pillar in Pokemon Emerald Pokemon Sapphire and Ruby
Metagross can be obtained when you finish the Elite Four and go to Stevens house and there will be a pokeball and a letter next to it in Mosdeep
Mighyena can be obtained by evolving Poochyena
Manetrec can be obtained by evolving Electrike
Tyranitar can be obtained by evolving Larvatar which is found in Sevault Canyon on island 7
(Mightyena Manetrec Metagross and Rayquaza can only be obtained in Emerald Ruby and Sapphire)

You have to Trade except for Tyranitar.

Larvitar the first evolution of tyranitar is found at seavault canyon in island 7.
The rest is only found in R/S/E

Jirachi =nintendo event?? I'm not sure
Rayquaza= Trade from Emerald/saphire/Ruby
Metagross=Evolve from beldum/metang not sure what level/Trade
Mightyena= Evolve from poocheyena/Trade
Magnetric= Evolve from electrike/Trade
Tyranitar=Evolve from larvitar/pupitar

If you need any more hints on where to find Pokemon, go to www.serebii.net. They have absolutely everything there.