So I have to admit one of the big turn offs for Black and White was that it didn't have previous gens.  I've searched but can't find any word on previous gen pokemon for x/y.  I want a 3DS Charizard!

We know that at a bunch of Gen 1 to 5 Pokemon will appear in Black/White. So far, the only one from G1 I know is making an appearance is Magikarp. Still, I imagine Charizard will be programmed into the game and will eventually make a playable debut.

Mewtwo is definitely in X and Y. That much is confirmed, as is Eevee being in (And therefore all it's evolutions too). I think this gen is going to be more like it was in Gen III, a decent sized group of newbies with an equally decent sized group of older Pokemon returning.

Black and White had gen 1 pokemon's, but you could only get them after finishing the main story.

X/Y seems to have eevee, mewtwo and pikachu so far.

Fire Red is still my favorite just because I like the starters the best though lol.  It's purely for nostalgic purposes but I really want Charmander, Bulbasaur (not sure if I spelt that right), and Squirtle in there.

They brought Charizard back in the anime, as well as Mewtwo.

Also Magikarp will be in X/Y.

I think the chances are pretty high!

But even if you can't capture them, it would be possible to trade them from previous games right?
I'm asking because I stop playing the game after Crystal :/

Not likely. Gen II (Gold/Silver/Crystal) couldn't trade to Gen III, which couldn't trade with Gen IV (Though your older pokemon could be brought forward through a post-story feature) and Gen IV couldn't trade with Gen V (Though again, you could bring them forward using a post-game feature). They seem to be revamping things a bit for Gen VI, but I'm guessing bringing anything from Gen V will only be allowed post game (especially since it's on a new system.)

I  see, thanks for your reply :)