For Gameshark, codes are generally XXXXXXXX:YYYY
The 8 X's are a RAM location where the game stores a given piece of information, say your characters HP or Max HP.
The Y's are usually a quantity, anywhere between 0 and FFFF, which =65535.
So when I open up The Legend of Zelda: The Minish Cap and check my code list I see the code 02002aec:0005 which means that I always have 5 bombs.
I have a bit of experience with Gameshark codes so maybe I can answer some questions for you.
