"This year's E3 is not Revolution's coming out party,"

[Smoke]

From this FAQ:


Item: Super leaf
What: You can press B to swing your tail at enemies (which only works
above water), or run for a while (hold B) until your P meter at
the bottom is full and the keep pressing B to fly (again, above
water only). If you get hit while using this, you go back to
super (big) Mario.


Item: Frog suit
What: A suit that gives you better control in water, as well as
allowing you to go past some currents that no other Mario can!
Don't bother using this on land though, since it is hard to
control. If you get hit while using this, you go back to super
(big) Mario.


Item: Tanooki suit
What: This gives you the power to, at your leisure, press down+B to
turn into an invincible statue for a short time. When you do so,
you will fall straight down (don't do it over a pit :P). If you
do this on an enemy, most likely you will kill it. This is the
only way to kill some enemies. You can also press B to swing
your tail at enemies (which only works above water), or run for
a while (hold B) until your P meter at the bottom is full and
then keep pressing B to fly (again, above water only). However,
although it seems that this would be a rare item, it is actually
quite common if you know where to look. If you get hit while
using this, you go back to super (big) Mario.


Item: Hammer brothers suit
What: A very rare item (you can only get 1 for certain on the map and
two in levels), this allows you to throw hammers which will kill
almost anything, including all fortress foes. When you duck in
it, it protects you from almost all projectiles. The problem
with this is its difficulty in aiming and its rarity (you won't
want to die with it on).If you get hit while using this, you go
back to super (big) Mario.

Here's a picture of the Super Mario Bros. 3 box that shows Mario in the racoon suit after using a super leaf.