spak i'm gonna assume you missed the IGN impressions?
the wiimote only control scheme is motion based for everything save ollies which is controled by the A button. i've seen a diagram somewhere that shows how tricks are performed;
manuals = tilt remote nose up
heelflips = tilt remote left (buttons facing left)
kickflilps = tilt remote right (buttons facing right)
etc...
they didnt get to see balance controls but think you'll still need the remote (probably to press A for ollies)
EDIT: i lied about the controls, i re-read the hands on preview which you can read for yourself
here (linked to second page, talks about controls).
if you're lazy, pretty much the only buttons used are A and B. A for kicks to build up speed, B to grab your board. The balance board mode was shown and it features a square showing you where you're leaning.
EDIT 2: Diagram i mentioned is in the newest GI mag. Shows how things will be controlled for Wii and DS.
I'd scan it but.. you know.
heres the gist of it:
DS: diagram of a skateboard will be on the touch screen, pointed at an angle like this: /
you draw a line over the skateboard to perform moves.
ie: draw a straight line from tail to nose = ollie
diagnol line off the right side of board= kick flip
line straight up from tail of board = hard flip
curved line from tail to the right = pop-shovit
cuved line from tail to the left - FS pop shovit
semi circle crossiing from one side of tail to other = 360 shovit
Wii: flick up = ollie
tilt left = kickflip (tilt right = hardflip)
tilt 180 = pop shovit (basically turn the controller till buttons are faced down)
tilt full circle = 360 pop shovit (dont know how the hell you'll do that easily..)
tilt up = manual
for those worried about just skating around using motion controls, you can plug in the nunchuk for analog steering