Here are some Cheats :

Astro Barrier
On the loading screen, press:
1 to go to level 10
2 to go to level 20
3 to go to level 30

Secret Agent
To become a secret agent, simply click the moderator logo at the upper right of the screen then answer the quiz. If you have answered all the questions correctly, you should recieved a spy phone on your next log in.

Agent Quiz Answers
Honest
Being mean or rude
Report them
Saying their address
I want to keep Club Penguin Safe
I want to help other penguins

Secret Dojo
Located at the upper right corner of the map in the mountains.

Cart Surfer
To get more coins from the cart surfer game which can be found on the mine shack, simply do this pattern. Down arrow key + space, space + left arrow key then grinds on turns. Then tip your cart on purpose, do the pattern again and finish the game with 1 life left. I usually get 500+ coins per game.

Nubbin
Go to the swf page and login, Press F11 to make it full screen, when you’re in the game click on the white part below your chat area and your penguin will walk right down and your finally nubbin.

Website
Go to http://www.clubpenguin.com, take a look at the upper right corner of the page, you will see a blue penguin then click on it to change his outfit. Secret 2, when you click the letter ‘N’ on the night club you will see what ninjas look like.

Walk on walls
First, go to town and stand 1 inch above your chat bar. Now click the tree near the arrow sign, just one click then immediately click on the coffee shop door. To go back and forth, just click the path way going to the dock then click the coffee shop door again.

Walking with a newspaper
First, go to http://play.clubpenguin.com/load.swf then go inside the book room and wait until somebody starts a game, join in when the ‘Do you want to join the game’ appears, click yes and go to the couch very fast. Drag a player card to the left and make sure the mail button is againts the left screen then click on the newspaper, now send a mail to anyone then dance. Now go to the town then go back to the place where you did the newspaper dance, you should be walking with a paper now. To check if it really works, try asking your friends.

Dancing with a newspaper
Go to http://play.clubpenguin.com/load.swf then click on anyone so that their player card will appear on your screen, drag the player card all the way to left corner and make sure the mail button is against the edge of the screen. Open the newspaper then click on the send mail button and send a message to that person, click on the actions button then dance.

Changing other peoples igloos
First, go to your igloo and click on the tape measure then use your spy phone to teleport to the headquarters. Open your map and go to other igloos then try moving their items. This is very simple, so i do not expect people asking questions on how to do it again.

Walking on lighthouse walls
First, go behind the fish filled bucket, then click on the door very quickly and click on the top of the room. If you executed the steps correctly, you will be walking on the lighthouse walls.

Robot dance
Take all of your penguin’s clothes off, so that all you can see is the paint. Click the star on your player card and wear the clown set, then move the window so that you will be able to see the actions button. Now choose dance, but take note that this glitch only works on client side which means only you can see it. Also, try doing it with other stuff on.

Throw snowballs very fast
For best quality go behind something that you cant walk over like the table in gift shop. Now press T on your keyboard and click on any spot to throw a snowball. By throwing snowballs simultaneously, you’ll end up with a big arch of snowballs.

105 buddies
For you to have 105 buddies, you’ll need to have 99 buddies or less. Click all of the people you want to be friends with, then wait 1 to 3 minutes for them to say yes. Go to your mail thingy and click ok to accept all friend requests. Now you will have more than 100 buddies.

Appear near the arrow sign
Go to the town then walk into the night club, once your inside click the top right corner on the exit door, keep clicking while its loading. Once it loaded completely you should appear by the arrow sign closest to the dock.

Stand on top of another penguin
Find a penguin you would like to stand on top of. Once you have chosen your target, push and hold down the tab button on your keyboard, however your mouse must be over your target while holding the key. Your cursor will turn into a regular mouse pointer and click on your target.

Big Red Fish
To catch the big fish you need to have 1 yellow then the big fish came and grab that little. And you get +50 Coins