[Update: It seems that the news is big enough to warrant its own Nintendo Direct! It'll run for 10 minutes at 8PM in Japan, 6AM EST and 11AM GMT on the 8th of January. You may wish to tune in and check it out, as something tells me that pokéfans will want to see it!]
About a week ago, trailers for Pokémon Black Version 2 and White Version 2 in Japan were showing a little announcement tacked at the end. They stated that there would be some news coming on the 8th, but considering that the trailers were advertising games that have been out for quite some time already, a lot of people just assumed that it was something to do with more downloadable pokémon.
However, the Japanese Pokémon website has recently updated, mentioning that there will be some big news coming on the 8th, and that you should bookmark the page and check back later. Things are starting to get a little more interesting here, but it could still mean anything, right?
The latest development in this crazy news saga is that the English Pokémon Twitter account has now mentioned that you should check the official site on the 8th for 'major' news. You might think that this could still be anything, and while that's certainly still a possibility, the key thing is that the English site is talking about this at all.
Many spin-offs, downloadable content and minor news is not spoken about by the English site until it becomes available outside of Japan. I mean, why announce a downloadable Pikachu or a new Mystery Dungeon game on the English site with no confirmation that they will leave Japan? No, this is apparently 'major' news, and I'd like to point out that the last time both sites announced something simultaneously, we heard about Pokémon Black Version and White Version for the first time, as well as the identity of the box art mascots.
So, that's about it. It could be absolutely nothing, but I'm certainly thinking we have a new game being announced. My bet would be the start of the sixth generation on the 3DS, but I'm sure there are many folks waiting for a potential Ruby/Sapphire remake. What do you think?