And finally a number of new Sugimori artworks have been released, including those of the final forms of the Isshu starters:

bulbanews.bulbagarden.net/wiki/Mew_distribution_starts_on_October_15th

Mew is now available for download via Mystery Gift on Heart Gold and Soul Silver from October 15 through October 30, 2010!

Since the images in Serebii's pokedex are currently unavailable due to NoA's copyright claim, some other Pokedex lists of the new Pokemon are found here and here:

veekun.com/dex/pokemon/search

pokemondb.net/pokedex/game/black-white

These would appear to be the Black/White version exclusives so far:

img188.imageshack.us/img188/6262/bwversionexclusive.jpg

Edit: So, the legal statements are real, but Serebii will be permitted to start posting images up subject to fair use. Very well.

Serebii also stated "As near as I can gather, the reason for the cease and desist was due to the posting of the images from Pokexperto, which were leaks and before the game came out and thus that annoyed Nintendo. Their lawyer then decided to get us to remove all images rather than the specific images"

It would 'appear' that Nintendo has released a legal statement to Serebii and Pokebeach requesting that all graphics/screenshots/etc taken from the Black and White games be removed due to copyright infringement.

bulbanews.bulbagarden.net/wiki/Fansites_served_with_copyright_infringement_notices

Hence, I noted such images have been removed from Serebii until further notice. However, there seems to be some errors with the emails which brings their validity into question, as a fellow named Ambi Pom Pom noted here:

archives.bulbagarden.net/media/upload/thumb/4/45/ArchaicBeachPost.png/800px-ArchaicBeachPost.png

Finally, the day of release in Japan! Information should get to be more comprehensive now with so many copies available.

Edit: Actually, it looks like it's being released right this moment. People are getting copies currently.

^^ If you meant there wasn't a Ground type Gym, there was- Viridian City. Giovanni was the only Ground Gym Leader previously. Hence the subtle name pun "Geo"vanni.

He had Rhyhorn, Dugtrio, Nidoqueen, Nidoking and Rhydon, and also gave out the Earth Badge.

Either way, there is a Ground type Gym in Isshu too.

All the new Pokemon sprites, here all in one post! :

victoryroad.net/showpost.php

Edit: Surprisingly, new scans show that Iris is in fact the 8th Gym Leader -of one version only!... so it comes full circle with Dent/Dento being one of the three 1st Gym Leaders, hanging out with Ash like the Gym Leaders Misty and Brock... though a powerful leader appearing so early? Interesting.

Also, Serebii released a scan showing most of the new Gyms(though there is a possibility these might be inaccurate)...

Gym 1) It's Dent/Dento and the other two with the elemental monkeys, so it could vary, possibly.
Gym 2) Normal(Aloe!)
Gym 3) Bug(male leader)
Gym 4) Electric(female leader)
Gym 5) Ground(male leader)
Gym 6) Flying(female leader)
Gym 7) Ice(male leader)
Gym 8) Dragon(Iris! which explains the Kibago she has with her)/(white-bearded male leader)

Elite 1) Ghost(female)
Elite 2) Dark(male)
Elite 3) Psychic(female)
Elite 4) Fighting(male)

Champion) ???

Here's a picture of Team Plasma's leader. He is said to be posing as a king/is a king/etc, which fits with the theme of them dressed as knights. Also, some proper artwork of the second stage evolutions: