in goldenrod city to the far left (past the radio tower)
yes
Chat with our AI personalities
You can only get a rayquaza by transferring it from heartgold or soulsilver or by the GTS.
yes
you cannot catch him i think. i think that you need to get him over GTS or migrate from Ruby, sapphire, or Emerald. Sorry if this statement doesn't help any. :[
you cant Actually, you can, but it could be risky. You can upload the Pokemon onto the GTS and then save switch the game cartridges and go to the GTS with that game and search for your Pokemon and then simply trade it with one from soul silver. Just make sure that you select a Pokemon you have in SoulSilver for the one looking for when you load the Pokemon up from Platinum. Or if it is a rare Pokemon you could always do it the opposite way and upload a weedle or something and put in what your Pokemon is (provided you have seen it) and then trade that way. I have done both ways and only had it not work out for me once because I was quick enough.
Yes, there is a GTS in Pokemon Black and White. It is up in the Pokemon Center and you can access it once you get the first badge as always.