Okay, guys. Newbie here. I'd like to open up a general location thread. What I mean by this is that it could be a location in which people could post and/or request the location of certain pokemon, be it common, rare, or legendary.

Personally, I'd like to know the location of a Larvitar or its evolutions, Mewtwo, Mew, Lugia, and Elekid.

Also, I'd like to know how the system works out with trade-evolutioin pokemon such as Alakazam and Steelix. Will I have to go out and capture those seperately, or is there a certain level at which my Onix and Kadabra will evolve naturally, via the game's hack?
Some pokemon I've found: 
*I'm only a bit into the game, so forgive me if these don't really help you out...

Starter pokemon: In a location I believe to be called the Altering Cave. It's in a cave after Slateport. After you beat Team Aqua, head north and take a right. At the end of the trail near the water's edge, there should be a cave. Inside will be all of the starters ranging from Bulbasaur to Torchic. A bit of warning though: Bulbasaurs, Cyndaquils, Charmanders, and Torchics seem to be much more common, while Mudkips, Squirtles, and Treekos are much harder to find. You'll also find a few Pikachus in here!

Many thanks to those who help me out, and many apologies if any rules have been broken.