Editing apps?

[nat130]

I was just wondering if it's possible to open up and app in the iPhone SDK to edit files and change code. It's probably a stupid question, and I'm totally new to all of the programming scene, but I thought it would be cool to open a simple app up and edit files, and maybe change the player character just for fun. Sorry if this is a really dumb question, or if it's in the wrong forum section or whatever...

So is it at all possible? Would it only work on a cracked app?

[Cer0]

Talk about cracked app/warez is not allowed. Old but closing anyway.