We now know a little bit more about the upcoming Generation Six games. According to serebii.net, the names of the two mascot Legendary Pokemon had been revealed.

The deer Pokemon who seems to be the mascot for Pokemon X is called Xerneas (ZURR-nee-us).

And the condor/wyvern-like Pokemon who's the mascot for Pokemon Y is called Yveltal (ee-VELL-tall).

That's all that's known about these two Pokemon at the moment. There's been nothing revealed about the myths/legends behind them, or even what their types are. I do have a few theories about what their types are, but I'm going to keep them to myself to avoid creating any rumors. It's probably a safe bet though that Yveltal is a Flying-type and something else. Anyway, at least we know what to call them.