A quick catch-up for anyone who is joining the thread and has any questions on how this all works.
- Games with an announced release date: Super Mario Galaxy 2 (available now), Donkey Kong Country Returns (Jan. 22nd in Europe), Punch-Out!! (Jan. 22nd in the US) and Metroid Prime Trilogy (Jan 29th). All of these titles will cost $20 (or regional equivalent), but they will be on sale for half price ($10 or regional equivalent) during their first week on the eShop.
- Games planned for future release, without specific release dates given: Kirby's Adventure Wii (aka Return to Dreamland in the US), Punch-Out!! (in Europe), Pandora's Tower and Sin & Punishment: Star Successor. I assume that DK Country Returns will be available some time in the future in the US as well.
- Super Mario Galaxy 2's download size is 1.3 GB.
- The Wii U Gamepad can be now used for both off-screen play AND as a control method in games that originally supported the Wii Classic Controller (Pro).
- Of the titles announced for Europe and the US, only Pandora's Tower and Sin & Punishment support the CCP.
- This means that, at this very moment, we do not know whether this feature will be implemented as a system-wide option or it will be restricted to eShop versions of Wii games. We will have to wait and see for any official confirmation on either possibility.
- There is no support for the Wii U Pro Controller or GameCube controller via adapter.
- eShop/Virtual Console Wii games are not HD remasters. They are the exact same Wii game that you can buy on disc, with the added advantage of not having to swap discs and being capable of skipping the vWii menu. The game seems to be running in vWii mode, for all intents and purposes (no Miiverse, Wii U menu, etc.).
- The Wii U Gamepad has a built-in sensor bar that can be used instead of the external one included with the Wii and Wii U. You still need a Wiimote + Nunchuk to play Super Mario Galaxy 2 (and any other game other than S&P and Pandora's Tower!).
The OP should be updated to reflect some of the most commonly-asked questions, because at least two or three people per page ask the same things over and over.
Personal note: My theory? Nintendo will release a patch that will implement the Gamepad features in a system-wide level between today and the release of the first CCP-compatible title, as part of their regular system update schedule. It'd make absolutely no sense to have such a feature for just a couple of (relatively minor) titles and not take advantage of it in any other game.