no you must have a gameshark to use gameshark code because there is no other way to enter them into the console but if you get a gameshark then many codes come downloaded on them so you don't have to...
In the GBA versions: Go to the Space Station. The man straight in front of you will say a certain number of successful launches. This increases every week. I have been told at 70, you can get Deoxys....
Nothing infinite will stay infinite. Codes that increase things like money will work but it won't be infinite without the gameshark (in other words some codes will make your money 9999999, or so but...
Well when you turn it on does it say ADD NEW GAME at the top if it does then I can help.The little cursor on the side is spinning right? Move that to ADD NEW GAME. Press B Now it shoul say enter game...