At the level selection screen, hold Select and press L, L, B, A, R.
In the fourth world, there is a level called "Don't look Back". When in the level, you should come around a cannon that shoots those cannons with the faces on them. Go on the cannon and jump up and down until you unlock a winged cloud. Hit it with an egg, and you shoukd get a "1 up". The first part of the level is quite hard, so every time you die, you can go back on the cannon and get the life. Also, go in the tube that is upside down and there is a middle ring in it. So don't skip it!
(supplied by: Lilshow08@aol.com)