Someone Said:
http://wii.com/jp/movies/smashbros-movie1/

Check around 4:20 in the lower-right-hand corner that shows who you can use the stickers on. Lucario's and Ness's heads appear in separate images:

Lucario: http://img341.imageshack.us/my.php?i...p439380np6.jpg

Ness: http://img341.imageshack.us/my.php?i...p542612bd3.jpg

Enjoy.

Credit: Edible from GFAQs

EDIT: People have been saying that the video on youtube just has blank bars at the lower-right where the icons are, but if you look in the one on wii.com, then they're there.

EDIT2:
Along the same lines, if you look at this screen:
http://www.smashbros.com/jp/gamemode...12_080118a.jpg
It's a typical sticker and there's nothing on the lower right.

But if you look at this one:
http://www.smashbros.com/jp/gamemode...12_080118b.jpg
There seems to be something off-screen.

This can mean either that there's an Animal Crossing character (that area shows what characters the sticker can be used on), very unlikely, or maybe it's just going to be people who can use magic attacks.

Argument against the latter is that even though not everyone can use slash attacks, the first pic's sticker isn't specialized for anyone.

EDIT3: Nintendo seemed to have put the video without the leak back onto wii.com. Though if you look in this thread, I'm sure you'd be convinced that it's real.